Warren R. Heymann, MD

To the Editor:

Erythema induratum, also known as nodular vasculitis, is a panniculitis that usually affects the lower extremities in middle-aged women. Classically, it has been described as a delayed-type hypersensitivity reaction to Mycobacterium tuberculosis, also known as a tuberculid.^1,2 Other infections, however, also have been implicated as causes of erythema induratum, including bacillus Calmette-Guérin (BCG), the attenuated form of Mycobacterium bovis, which commonly is used for tuberculosis vaccination. Medications also may cause erythema induratum. The characteristic distribution of the nodules on the posterior calves helps to distinguish erythema induratum from other panniculitides. A PubMed search of articles indexed for MEDLINE using the term disseminated erythema induratum revealed few case reports documenting nodules on the arms, thighs, or chest, and only 1 case report of disseminated erythema induratum.^3-8 We describe a rare combination of disseminated erythema induratum in a patient with remote exposure to tuberculosis and recent BCG exposure.

An 88-year-old woman presented for evaluation of violaceous, minimally tender, nonulcerated, subcutaneous nodules on the legs, arms, and trunk of several weeks’ duration (Figure 1). She had a remote history of tuberculosis as a child, prior to the advent of modern antituberculosis regimens. Her medical history also included hypertension, breast cancer treated with lymph node dissection, gastroesophageal reflux disease, and bladder cancer treated with intravesical BCG 10 years prior to the onset of the nodules. She reported minimal coughing and a 25-lb weight loss over the last year, but she denied night sweats, fever, or chills.

Disseminated erythema induratum, an exceptionally rare variant of panniculitis, may be seen in patients with a remote history of M tuberculosis exposure and/or recent therapeutic BCG exposure. It is imperative to rule out active tuberculosis, especially in elderly patients whose disease predated the advent of modern antituberculosis therapy. Using an IFN-γ release assay in addition to chest radiographs and other clinical stigmata allows differentiation of the etiology of erythema induratum in those patients with tuberculosis who also were treated with BCG.

To the Editor:

Erythema induratum, also known as nodular vasculitis, is a panniculitis that usually affects the lower extremities in middle-aged women. Classically, it has been described as a delayed-type hypersensitivity reaction to Mycobacterium tuberculosis, also known as a tuberculid.^1,2 Other infections, however, also have been implicated as causes of erythema induratum, including bacillus Calmette-Guérin (BCG), the attenuated form of Mycobacterium bovis, which commonly is used for tuberculosis vaccination. Medications also may cause erythema induratum. The characteristic distribution of the nodules on the posterior calves helps to distinguish erythema induratum from other panniculitides. A PubMed search of articles indexed for MEDLINE using the term disseminated erythema induratum revealed few case reports documenting nodules on the arms, thighs, or chest, and only 1 case report of disseminated erythema induratum.^3-8 We describe a rare combination of disseminated erythema induratum in a patient with remote exposure to tuberculosis and recent BCG exposure.

An 88-year-old woman presented for evaluation of violaceous, minimally tender, nonulcerated, subcutaneous nodules on the legs, arms, and trunk of several weeks’ duration (Figure 1). She had a remote history of tuberculosis as a child, prior to the advent of modern antituberculosis regimens. Her medical history also included hypertension, breast cancer treated with lymph node dissection, gastroesophageal reflux disease, and bladder cancer treated with intravesical BCG 10 years prior to the onset of the nodules. She reported minimal coughing and a 25-lb weight loss over the last year, but she denied night sweats, fever, or chills.

Disseminated erythema induratum, an exceptionally rare variant of panniculitis, may be seen in patients with a remote history of M tuberculosis exposure and/or recent therapeutic BCG exposure. It is imperative to rule out active tuberculosis, especially in elderly patients whose disease predated the advent of modern antituberculosis therapy. Using an IFN-γ release assay in addition to chest radiographs and other clinical stigmata allows differentiation of the etiology of erythema induratum in those patients with tuberculosis who also were treated with BCG.

To the Editor:

Erythema induratum, also known as nodular vasculitis, is a panniculitis that usually affects the lower extremities in middle-aged women. Classically, it has been described as a delayed-type hypersensitivity reaction to Mycobacterium tuberculosis, also known as a tuberculid.^1,2 Other infections, however, also have been implicated as causes of erythema induratum, including bacillus Calmette-Guérin (BCG), the attenuated form of Mycobacterium bovis, which commonly is used for tuberculosis vaccination. Medications also may cause erythema induratum. The characteristic distribution of the nodules on the posterior calves helps to distinguish erythema induratum from other panniculitides. A PubMed search of articles indexed for MEDLINE using the term disseminated erythema induratum revealed few case reports documenting nodules on the arms, thighs, or chest, and only 1 case report of disseminated erythema induratum.^3-8 We describe a rare combination of disseminated erythema induratum in a patient with remote exposure to tuberculosis and recent BCG exposure.

An 88-year-old woman presented for evaluation of violaceous, minimally tender, nonulcerated, subcutaneous nodules on the legs, arms, and trunk of several weeks’ duration (Figure 1). She had a remote history of tuberculosis as a child, prior to the advent of modern antituberculosis regimens. Her medical history also included hypertension, breast cancer treated with lymph node dissection, gastroesophageal reflux disease, and bladder cancer treated with intravesical BCG 10 years prior to the onset of the nodules. She reported minimal coughing and a 25-lb weight loss over the last year, but she denied night sweats, fever, or chills.

Disseminated erythema induratum, an exceptionally rare variant of panniculitis, may be seen in patients with a remote history of M tuberculosis exposure and/or recent therapeutic BCG exposure. It is imperative to rule out active tuberculosis, especially in elderly patients whose disease predated the advent of modern antituberculosis therapy. Using an IFN-γ release assay in addition to chest radiographs and other clinical stigmata allows differentiation of the etiology of erythema induratum in those patients with tuberculosis who also were treated with BCG.

The Diagnosis: Congenital Self-healing Reticulohistiocytosis 

Biopsy of a representative lesion from this patient was consistent with congenital self-healing reticulohistiocytosis, as shown in the Figure. Characteristic Langerhans cells were present in the dermis that stained CD1a positive, S-100 positive, and CD68 negative to confirm the diagnosis.

Congenital self-healing reticulohistiocytosis, or Hashimoto-Pritzker syndrome, is a rare benign form of Langerhans cell histiocytosis. It is twice as common in males than females and typically noted at birth or early during the neonatal period. Lesions may present as pink, firm, asymptomatic papulonodular lesions that often ulcerate with possible residual hypopigmentation or hyperpigmentation.¹ The differential diagnosis includes congenital infectious and hematologic diseases typically associated with blueberry muffin baby. Thus, varicella, cytomegalovirus, syphilis, toxoplasmosis, rubella, neuroblastoma, leukemia cutis, and extramedullary hematopoiesis, among others, may be considered. Juvenile xanthogranuloma or urticaria pigmentosa also enter the differential diagnosis given the yellow-brown appearance. As a clonal proliferation of Langerhans cells, pathology reveals lesions that stain positive for CD1a and S-100.²  

Although typically absent, evaluation for systemic involvement is warranted, which may be an early presentation of multisystem Langerhans cell histiocytosis. Continued monitoring is recommended given the risk of relapse and associated mortality. Our patient continues to do well. He will continue to be followed by our team and hematology/oncology during early childhood.  

The treatment of congenital self-healing reticulohistiocytosis may include conservative monitoring, topical steroids, topical nitrogen mustard, tacrolimus, or psoralen plus UVA.³ Surgical excision may be considered for large lesions.  

The Diagnosis: Congenital Self-healing Reticulohistiocytosis 

Biopsy of a representative lesion from this patient was consistent with congenital self-healing reticulohistiocytosis, as shown in the Figure. Characteristic Langerhans cells were present in the dermis that stained CD1a positive, S-100 positive, and CD68 negative to confirm the diagnosis.

Congenital self-healing reticulohistiocytosis, or Hashimoto-Pritzker syndrome, is a rare benign form of Langerhans cell histiocytosis. It is twice as common in males than females and typically noted at birth or early during the neonatal period. Lesions may present as pink, firm, asymptomatic papulonodular lesions that often ulcerate with possible residual hypopigmentation or hyperpigmentation.¹ The differential diagnosis includes congenital infectious and hematologic diseases typically associated with blueberry muffin baby. Thus, varicella, cytomegalovirus, syphilis, toxoplasmosis, rubella, neuroblastoma, leukemia cutis, and extramedullary hematopoiesis, among others, may be considered. Juvenile xanthogranuloma or urticaria pigmentosa also enter the differential diagnosis given the yellow-brown appearance. As a clonal proliferation of Langerhans cells, pathology reveals lesions that stain positive for CD1a and S-100.²  

Although typically absent, evaluation for systemic involvement is warranted, which may be an early presentation of multisystem Langerhans cell histiocytosis. Continued monitoring is recommended given the risk of relapse and associated mortality. Our patient continues to do well. He will continue to be followed by our team and hematology/oncology during early childhood.  

The treatment of congenital self-healing reticulohistiocytosis may include conservative monitoring, topical steroids, topical nitrogen mustard, tacrolimus, or psoralen plus UVA.³ Surgical excision may be considered for large lesions.  

The Diagnosis: Congenital Self-healing Reticulohistiocytosis 

Biopsy of a representative lesion from this patient was consistent with congenital self-healing reticulohistiocytosis, as shown in the Figure. Characteristic Langerhans cells were present in the dermis that stained CD1a positive, S-100 positive, and CD68 negative to confirm the diagnosis.

Congenital self-healing reticulohistiocytosis, or Hashimoto-Pritzker syndrome, is a rare benign form of Langerhans cell histiocytosis. It is twice as common in males than females and typically noted at birth or early during the neonatal period. Lesions may present as pink, firm, asymptomatic papulonodular lesions that often ulcerate with possible residual hypopigmentation or hyperpigmentation.¹ The differential diagnosis includes congenital infectious and hematologic diseases typically associated with blueberry muffin baby. Thus, varicella, cytomegalovirus, syphilis, toxoplasmosis, rubella, neuroblastoma, leukemia cutis, and extramedullary hematopoiesis, among others, may be considered. Juvenile xanthogranuloma or urticaria pigmentosa also enter the differential diagnosis given the yellow-brown appearance. As a clonal proliferation of Langerhans cells, pathology reveals lesions that stain positive for CD1a and S-100.²  

Although typically absent, evaluation for systemic involvement is warranted, which may be an early presentation of multisystem Langerhans cell histiocytosis. Continued monitoring is recommended given the risk of relapse and associated mortality. Our patient continues to do well. He will continue to be followed by our team and hematology/oncology during early childhood.  

The treatment of congenital self-healing reticulohistiocytosis may include conservative monitoring, topical steroids, topical nitrogen mustard, tacrolimus, or psoralen plus UVA.³ Surgical excision may be considered for large lesions.  

Cutaneous manifestations of systemic lupus erythematosus (SLE) can be classified as lupus-specific or lupus-nonspecific skin lesions. Lupus-specific lesions commonly are photodistributed, with involvement of the malar region, arms, and trunk. The development of discoid lupus erythematosus (DLE) in areas of trauma, including sun-exposed skin, is not uncommon and may be associated with an isomorphic response. We present a rare case of an isomorphic response following herpes zoster (HZ) in a young woman undergoing treatment with immunosuppressive agents for SLE and DLE. Potential prophylactic therapy also is discussed.

Case Report

A 19-year-old woman initially presented to an outside dermatologist for evaluation of new-onset scarring alopecia, crusted erythematous plaques on the face and arms, and arthralgia. A punch biopsy of a lesion on the left arm demonstrated a lichenoid and perivascular lymphocytic infiltrate with scattered necrotic keratinocytes, perifollicular inflammation, and focally thickened basement membrane at the dermoepidermal junction consistent with discoid lupus erythematosus (DLE). A laboratory workup for SLE revealed 1:1280 antinuclear antibodies (reference range, negative <1:80) with elevated titers of double-stranded DNA, Smith, ribonucleoprotein, Sjögren syndrome A, and Sjögren syndrome B autoantibodies with low complement levels. Based on these findings, a diagnosis of SLE and DLE was made.

At that time, the patient was started on hydroxychloroquine 200 mg twice daily for SLE. Four days later she developed swelling in both hands and feet, and hydroxychloroquine was stopped due to a presumed adverse reaction; however, her symptoms subsequently were determined to be polyarthritis secondary to a lupus flare. Prednisone 10 mg once daily was then initiated. The patient was encouraged to restart hydroxychloroquine, but she declined.

Over the next 13 months, the patient developed severe photosensitivity, oral ulcers, Raynaud phenomenon, anemia, and nephrotic-range proteinuria. She ultimately was diagnosed by the nephrology department at our institution with mixed diffuse proliferative and membranous glomerulonephritis. Induction therapy with oral mycophenolate mofetil 1000 mg twice daily and prednisone 60 mg once daily was started, followed by the addition of tacrolimus 1 mg twice daily. Despite immunosuppressive therapy, she continued to develop new discoid lesions on the face, chest, and arms. The disease course also was complicated by a pulmonary embolism and deep venous thrombosis, for which the hematology department initiated treatment with warfarin for anticoagulation. Anticardiolipin antibodies were negative at presentation and again 12 weeks later.

After 4 weeks of treatment with mycophenolate mofetil, prednisone, and tacrolimus, the patient developed a painful vesicular rash on the left breast with extension over the left axilla and scapula in a T3 to T4 dermatomal distribution. A clinical diagnosis of HZ was made, and she was started on intravenous acyclovir 10 mg/kg in dextrose 5% every 8 hours for 4 days followed by oral valacyclovir 1000 mg every 8 hours for 14 days, which led to resolution of the eruption.

Over the next 4 months, the patient continued to experience pain confined to the same dermatomal area as the HZ, which was consistent with postherpetic neuralgia. Mycophenolate mofetil was discontinued after she developed acute liver toxicity attributed to the drug. Upon discontinuation, the patient developed a new pruritic rash on both arms and the back. Physical examination by the dermatology department at our institution revealed diffuse, scaly, hyperpigmented papules and annular plaques with central pink hypopigmentation on the face, ears, anterior chest, arms, hands, and back. On the left anterior chest and back, the distribution was strikingly unilateral and multidermatomal (Figure 1). Upon further questioning, the patient confirmed that the areas of the new rash coincided with areas previously affected by HZ. Histologic examination of a representative lesion from the left lateral breast revealed hyperkeratosis, follicular plugging, a patchy lichenoid and perivascular mononuclear cell infiltrate, and pigment incontinence (Figure 2A). These histologic features were subtle and were not diagnostic for lupus; however, direct immunofluorescence demonstrated a continuous granular band of IgG and C3 along the dermoepidermal junction, confirming the diagnosis of DLE (Figure 2B). The histologic findings and clinical presentation were consistent with the development of DLE in areas of previous trauma from HZ. The patient continues to follow-up with the rheumatology and nephrology departments but was lost to dermatology follow-up.

Comment

The pathogenesis of DLE is poorly understood but is thought to be multifactorial, involving genetics, sun exposure, and immune dysregulation.¹ Development of DLE lesions in skin traumatized by tattoos, scratches, scars, and prolonged heat exposure has been reported.² Clarification of the mechanism(s) underlying these traumatized areas may provide insight into the pathophysiology of DLE.

The isomorphic response, also known as the Köbner phenomenon, is the development of a preexisting skin condition at a site of trauma. This phenomenon has been observed in several dermatologic conditions including psoriasis, lichen planus, systemic sclerosis, dermatomyositis, sarcoidosis, vitiligo, and DLE.³ Koebnerization may result from trauma to the skin caused by scratches, sun exposure, radiography, prolonged heat and cold exposure, pressure, tattoos, scars, and inflammatory dermatoses.^2,4 Ueki⁴ suggested that localized trauma to the skin stimulates an immune response that makes the traumatized site a target for a preexisting skin condition. Inflammatory mediators such as IL-1, tumor necrosis factor α, IL-6, and interferon γ have been implicated in the pathophysiology of the isomorphic response.⁴

Wolf isotopic response is a similar entity that refers to the development of a novel skin condition at the site of a distinct, previously resolved skin disorder. This phenomenon was described by Wolf et al⁵ in 1995, and since then over 170 cases have been reported.^5-7 In most cases the initial skin condition is HZ, although herpes simplex virus has also been implicated. The common resulting skin conditions include granulomatous reactions, malignant tumors, lichen planus, morphea, and infections. The notion that the antecedent skin disease alters the affected site and causes it to be more susceptible to autoimmunity has been proposed as a mechanism for the isotopic response.^7,8 While one might consider our presentation of DLE following HZ to be an isotopic response, we believe this case is best classified as an isomorphic response, as the patient already had an established diagnosis of DLE.

The development of DLE at the site of a previous HZ eruption has been described in 2 other cases of young women with SLE.^9,10 Unique to our case is the development of a multidermatomal eruption, which may be an indication of her degree of immunosuppression, as immunosuppressed patients are more likely to present with multidermatomal reactivation of varicella zoster virus and postherpetic neuralgia.¹¹ The similarities between our case and the 2 prior reports—including the patients’ age, sex, history of SLE, and degree of immunosuppression—are noteworthy in that they may represent a subset of SLE patients who are predisposed to developing koebnerization following HZ. Physicians should be aware of this phenomenon and consider being proactive in preventing long-term damage.

When feasible, physicians should consider administering the HZ vaccine to reduce the course and severity of HZ before prescribing immunosuppressive agents. When HZ presents in young, immunosuppressed women with a history of SLE, we suggest monitoring the affected sites closely for any evidence of DLE. Topical corticosteroids should be applied to involved areas of the face or body at the earliest appearance of such lesions, which may prevent the isomorphic response and its potentially scarring DLE lesions. This will be our therapeutic approach if we encounter a similar clinical situation in the future. Further studies are warranted to assess the efficacy and optimal duration of this approach, which to our knowledge has not been reported in the literature. It may be that aggressive treatment for a few weeks can preclude the further development of DLE lesions; however, DLE lesions may appear in susceptible skin months after the HZ has resolved.

Acknowledgment
We thank Carolyn E. Grotkowski, MD, from the Department of Pathology, Cooper Medical School of Rowan University, Camden, New Jersey, for her assistance in photographing the pathology slides.

Cutaneous manifestations of systemic lupus erythematosus (SLE) can be classified as lupus-specific or lupus-nonspecific skin lesions. Lupus-specific lesions commonly are photodistributed, with involvement of the malar region, arms, and trunk. The development of discoid lupus erythematosus (DLE) in areas of trauma, including sun-exposed skin, is not uncommon and may be associated with an isomorphic response. We present a rare case of an isomorphic response following herpes zoster (HZ) in a young woman undergoing treatment with immunosuppressive agents for SLE and DLE. Potential prophylactic therapy also is discussed.

Case Report

A 19-year-old woman initially presented to an outside dermatologist for evaluation of new-onset scarring alopecia, crusted erythematous plaques on the face and arms, and arthralgia. A punch biopsy of a lesion on the left arm demonstrated a lichenoid and perivascular lymphocytic infiltrate with scattered necrotic keratinocytes, perifollicular inflammation, and focally thickened basement membrane at the dermoepidermal junction consistent with discoid lupus erythematosus (DLE). A laboratory workup for SLE revealed 1:1280 antinuclear antibodies (reference range, negative <1:80) with elevated titers of double-stranded DNA, Smith, ribonucleoprotein, Sjögren syndrome A, and Sjögren syndrome B autoantibodies with low complement levels. Based on these findings, a diagnosis of SLE and DLE was made.

At that time, the patient was started on hydroxychloroquine 200 mg twice daily for SLE. Four days later she developed swelling in both hands and feet, and hydroxychloroquine was stopped due to a presumed adverse reaction; however, her symptoms subsequently were determined to be polyarthritis secondary to a lupus flare. Prednisone 10 mg once daily was then initiated. The patient was encouraged to restart hydroxychloroquine, but she declined.

Over the next 13 months, the patient developed severe photosensitivity, oral ulcers, Raynaud phenomenon, anemia, and nephrotic-range proteinuria. She ultimately was diagnosed by the nephrology department at our institution with mixed diffuse proliferative and membranous glomerulonephritis. Induction therapy with oral mycophenolate mofetil 1000 mg twice daily and prednisone 60 mg once daily was started, followed by the addition of tacrolimus 1 mg twice daily. Despite immunosuppressive therapy, she continued to develop new discoid lesions on the face, chest, and arms. The disease course also was complicated by a pulmonary embolism and deep venous thrombosis, for which the hematology department initiated treatment with warfarin for anticoagulation. Anticardiolipin antibodies were negative at presentation and again 12 weeks later.

After 4 weeks of treatment with mycophenolate mofetil, prednisone, and tacrolimus, the patient developed a painful vesicular rash on the left breast with extension over the left axilla and scapula in a T3 to T4 dermatomal distribution. A clinical diagnosis of HZ was made, and she was started on intravenous acyclovir 10 mg/kg in dextrose 5% every 8 hours for 4 days followed by oral valacyclovir 1000 mg every 8 hours for 14 days, which led to resolution of the eruption.

Over the next 4 months, the patient continued to experience pain confined to the same dermatomal area as the HZ, which was consistent with postherpetic neuralgia. Mycophenolate mofetil was discontinued after she developed acute liver toxicity attributed to the drug. Upon discontinuation, the patient developed a new pruritic rash on both arms and the back. Physical examination by the dermatology department at our institution revealed diffuse, scaly, hyperpigmented papules and annular plaques with central pink hypopigmentation on the face, ears, anterior chest, arms, hands, and back. On the left anterior chest and back, the distribution was strikingly unilateral and multidermatomal (Figure 1). Upon further questioning, the patient confirmed that the areas of the new rash coincided with areas previously affected by HZ. Histologic examination of a representative lesion from the left lateral breast revealed hyperkeratosis, follicular plugging, a patchy lichenoid and perivascular mononuclear cell infiltrate, and pigment incontinence (Figure 2A). These histologic features were subtle and were not diagnostic for lupus; however, direct immunofluorescence demonstrated a continuous granular band of IgG and C3 along the dermoepidermal junction, confirming the diagnosis of DLE (Figure 2B). The histologic findings and clinical presentation were consistent with the development of DLE in areas of previous trauma from HZ. The patient continues to follow-up with the rheumatology and nephrology departments but was lost to dermatology follow-up.

Comment

The pathogenesis of DLE is poorly understood but is thought to be multifactorial, involving genetics, sun exposure, and immune dysregulation.¹ Development of DLE lesions in skin traumatized by tattoos, scratches, scars, and prolonged heat exposure has been reported.² Clarification of the mechanism(s) underlying these traumatized areas may provide insight into the pathophysiology of DLE.

The isomorphic response, also known as the Köbner phenomenon, is the development of a preexisting skin condition at a site of trauma. This phenomenon has been observed in several dermatologic conditions including psoriasis, lichen planus, systemic sclerosis, dermatomyositis, sarcoidosis, vitiligo, and DLE.³ Koebnerization may result from trauma to the skin caused by scratches, sun exposure, radiography, prolonged heat and cold exposure, pressure, tattoos, scars, and inflammatory dermatoses.^2,4 Ueki⁴ suggested that localized trauma to the skin stimulates an immune response that makes the traumatized site a target for a preexisting skin condition. Inflammatory mediators such as IL-1, tumor necrosis factor α, IL-6, and interferon γ have been implicated in the pathophysiology of the isomorphic response.⁴

Wolf isotopic response is a similar entity that refers to the development of a novel skin condition at the site of a distinct, previously resolved skin disorder. This phenomenon was described by Wolf et al⁵ in 1995, and since then over 170 cases have been reported.^5-7 In most cases the initial skin condition is HZ, although herpes simplex virus has also been implicated. The common resulting skin conditions include granulomatous reactions, malignant tumors, lichen planus, morphea, and infections. The notion that the antecedent skin disease alters the affected site and causes it to be more susceptible to autoimmunity has been proposed as a mechanism for the isotopic response.^7,8 While one might consider our presentation of DLE following HZ to be an isotopic response, we believe this case is best classified as an isomorphic response, as the patient already had an established diagnosis of DLE.

The development of DLE at the site of a previous HZ eruption has been described in 2 other cases of young women with SLE.^9,10 Unique to our case is the development of a multidermatomal eruption, which may be an indication of her degree of immunosuppression, as immunosuppressed patients are more likely to present with multidermatomal reactivation of varicella zoster virus and postherpetic neuralgia.¹¹ The similarities between our case and the 2 prior reports—including the patients’ age, sex, history of SLE, and degree of immunosuppression—are noteworthy in that they may represent a subset of SLE patients who are predisposed to developing koebnerization following HZ. Physicians should be aware of this phenomenon and consider being proactive in preventing long-term damage.

When feasible, physicians should consider administering the HZ vaccine to reduce the course and severity of HZ before prescribing immunosuppressive agents. When HZ presents in young, immunosuppressed women with a history of SLE, we suggest monitoring the affected sites closely for any evidence of DLE. Topical corticosteroids should be applied to involved areas of the face or body at the earliest appearance of such lesions, which may prevent the isomorphic response and its potentially scarring DLE lesions. This will be our therapeutic approach if we encounter a similar clinical situation in the future. Further studies are warranted to assess the efficacy and optimal duration of this approach, which to our knowledge has not been reported in the literature. It may be that aggressive treatment for a few weeks can preclude the further development of DLE lesions; however, DLE lesions may appear in susceptible skin months after the HZ has resolved.

Acknowledgment
We thank Carolyn E. Grotkowski, MD, from the Department of Pathology, Cooper Medical School of Rowan University, Camden, New Jersey, for her assistance in photographing the pathology slides.

Cutaneous manifestations of systemic lupus erythematosus (SLE) can be classified as lupus-specific or lupus-nonspecific skin lesions. Lupus-specific lesions commonly are photodistributed, with involvement of the malar region, arms, and trunk. The development of discoid lupus erythematosus (DLE) in areas of trauma, including sun-exposed skin, is not uncommon and may be associated with an isomorphic response. We present a rare case of an isomorphic response following herpes zoster (HZ) in a young woman undergoing treatment with immunosuppressive agents for SLE and DLE. Potential prophylactic therapy also is discussed.

Case Report

A 19-year-old woman initially presented to an outside dermatologist for evaluation of new-onset scarring alopecia, crusted erythematous plaques on the face and arms, and arthralgia. A punch biopsy of a lesion on the left arm demonstrated a lichenoid and perivascular lymphocytic infiltrate with scattered necrotic keratinocytes, perifollicular inflammation, and focally thickened basement membrane at the dermoepidermal junction consistent with discoid lupus erythematosus (DLE). A laboratory workup for SLE revealed 1:1280 antinuclear antibodies (reference range, negative <1:80) with elevated titers of double-stranded DNA, Smith, ribonucleoprotein, Sjögren syndrome A, and Sjögren syndrome B autoantibodies with low complement levels. Based on these findings, a diagnosis of SLE and DLE was made.

At that time, the patient was started on hydroxychloroquine 200 mg twice daily for SLE. Four days later she developed swelling in both hands and feet, and hydroxychloroquine was stopped due to a presumed adverse reaction; however, her symptoms subsequently were determined to be polyarthritis secondary to a lupus flare. Prednisone 10 mg once daily was then initiated. The patient was encouraged to restart hydroxychloroquine, but she declined.

Over the next 13 months, the patient developed severe photosensitivity, oral ulcers, Raynaud phenomenon, anemia, and nephrotic-range proteinuria. She ultimately was diagnosed by the nephrology department at our institution with mixed diffuse proliferative and membranous glomerulonephritis. Induction therapy with oral mycophenolate mofetil 1000 mg twice daily and prednisone 60 mg once daily was started, followed by the addition of tacrolimus 1 mg twice daily. Despite immunosuppressive therapy, she continued to develop new discoid lesions on the face, chest, and arms. The disease course also was complicated by a pulmonary embolism and deep venous thrombosis, for which the hematology department initiated treatment with warfarin for anticoagulation. Anticardiolipin antibodies were negative at presentation and again 12 weeks later.

After 4 weeks of treatment with mycophenolate mofetil, prednisone, and tacrolimus, the patient developed a painful vesicular rash on the left breast with extension over the left axilla and scapula in a T3 to T4 dermatomal distribution. A clinical diagnosis of HZ was made, and she was started on intravenous acyclovir 10 mg/kg in dextrose 5% every 8 hours for 4 days followed by oral valacyclovir 1000 mg every 8 hours for 14 days, which led to resolution of the eruption.

Over the next 4 months, the patient continued to experience pain confined to the same dermatomal area as the HZ, which was consistent with postherpetic neuralgia. Mycophenolate mofetil was discontinued after she developed acute liver toxicity attributed to the drug. Upon discontinuation, the patient developed a new pruritic rash on both arms and the back. Physical examination by the dermatology department at our institution revealed diffuse, scaly, hyperpigmented papules and annular plaques with central pink hypopigmentation on the face, ears, anterior chest, arms, hands, and back. On the left anterior chest and back, the distribution was strikingly unilateral and multidermatomal (Figure 1). Upon further questioning, the patient confirmed that the areas of the new rash coincided with areas previously affected by HZ. Histologic examination of a representative lesion from the left lateral breast revealed hyperkeratosis, follicular plugging, a patchy lichenoid and perivascular mononuclear cell infiltrate, and pigment incontinence (Figure 2A). These histologic features were subtle and were not diagnostic for lupus; however, direct immunofluorescence demonstrated a continuous granular band of IgG and C3 along the dermoepidermal junction, confirming the diagnosis of DLE (Figure 2B). The histologic findings and clinical presentation were consistent with the development of DLE in areas of previous trauma from HZ. The patient continues to follow-up with the rheumatology and nephrology departments but was lost to dermatology follow-up.

Comment

The pathogenesis of DLE is poorly understood but is thought to be multifactorial, involving genetics, sun exposure, and immune dysregulation.¹ Development of DLE lesions in skin traumatized by tattoos, scratches, scars, and prolonged heat exposure has been reported.² Clarification of the mechanism(s) underlying these traumatized areas may provide insight into the pathophysiology of DLE.

The isomorphic response, also known as the Köbner phenomenon, is the development of a preexisting skin condition at a site of trauma. This phenomenon has been observed in several dermatologic conditions including psoriasis, lichen planus, systemic sclerosis, dermatomyositis, sarcoidosis, vitiligo, and DLE.³ Koebnerization may result from trauma to the skin caused by scratches, sun exposure, radiography, prolonged heat and cold exposure, pressure, tattoos, scars, and inflammatory dermatoses.^2,4 Ueki⁴ suggested that localized trauma to the skin stimulates an immune response that makes the traumatized site a target for a preexisting skin condition. Inflammatory mediators such as IL-1, tumor necrosis factor α, IL-6, and interferon γ have been implicated in the pathophysiology of the isomorphic response.⁴

Wolf isotopic response is a similar entity that refers to the development of a novel skin condition at the site of a distinct, previously resolved skin disorder. This phenomenon was described by Wolf et al⁵ in 1995, and since then over 170 cases have been reported.^5-7 In most cases the initial skin condition is HZ, although herpes simplex virus has also been implicated. The common resulting skin conditions include granulomatous reactions, malignant tumors, lichen planus, morphea, and infections. The notion that the antecedent skin disease alters the affected site and causes it to be more susceptible to autoimmunity has been proposed as a mechanism for the isotopic response.^7,8 While one might consider our presentation of DLE following HZ to be an isotopic response, we believe this case is best classified as an isomorphic response, as the patient already had an established diagnosis of DLE.

The development of DLE at the site of a previous HZ eruption has been described in 2 other cases of young women with SLE.^9,10 Unique to our case is the development of a multidermatomal eruption, which may be an indication of her degree of immunosuppression, as immunosuppressed patients are more likely to present with multidermatomal reactivation of varicella zoster virus and postherpetic neuralgia.¹¹ The similarities between our case and the 2 prior reports—including the patients’ age, sex, history of SLE, and degree of immunosuppression—are noteworthy in that they may represent a subset of SLE patients who are predisposed to developing koebnerization following HZ. Physicians should be aware of this phenomenon and consider being proactive in preventing long-term damage.

When feasible, physicians should consider administering the HZ vaccine to reduce the course and severity of HZ before prescribing immunosuppressive agents. When HZ presents in young, immunosuppressed women with a history of SLE, we suggest monitoring the affected sites closely for any evidence of DLE. Topical corticosteroids should be applied to involved areas of the face or body at the earliest appearance of such lesions, which may prevent the isomorphic response and its potentially scarring DLE lesions. This will be our therapeutic approach if we encounter a similar clinical situation in the future. Further studies are warranted to assess the efficacy and optimal duration of this approach, which to our knowledge has not been reported in the literature. It may be that aggressive treatment for a few weeks can preclude the further development of DLE lesions; however, DLE lesions may appear in susceptible skin months after the HZ has resolved.

Acknowledgment
We thank Carolyn E. Grotkowski, MD, from the Department of Pathology, Cooper Medical School of Rowan University, Camden, New Jersey, for her assistance in photographing the pathology slides.

Bullous pemphigoid (BP) is an acquired, autoimmune, subepidermal blistering disease that is more common in elderly patients.¹ An association with internal neoplasms and BP has been established; however, there is debate regarding the precise nature of the relationship.² Several gastrointestinal tract tumors have been associated with BP, including adenocarcinoma of the colon, adenosquamous cell carcinoma and adenocarcinoma of the stomach, adenocarcinoma of the rectum, and liver and bile duct malignancies.^3-5 Association with pancreatic neoplasms (eg, carcinoma of the pancreas) rarely has been reported.^5-7 We present an unusual case of a lymphoepithelial cyst of the pancreas in a patient with BP.

Case Report

A 67-year-old man presented with erythematous crusted plaques and pink scars over the chest, back, arms, and legs (Figure 1). A 1.5-cm tense bullous lesion was observed on the right knee. The patient’s medical history was notable for biopsy-proven BP of 8 months’ duration as well as diabetes mellitus and hypothyroidism. The patient was being followed by his surgeon for a 1.9-cm soft-tissue lesion in the pancreatic tail and was awaiting surgical excision at the time of the current presentation. The pancreatic lesion was discovered incidentally on magnetic resonance imaging performed following urologic concerns. At the current presentation, the patient’s medications included nifedipine, hydralazine, metoprolol, torsemide, aspirin, levothyroxine, atorvastatin, insulin lispro, and insulin glargine. He had previously been treated for BP with prednisone at a maximum dosage of 60 mg daily, clobetasol propionate cream 0.05%, and mupirocin ointment 2% without improvement. Because of substantial weight gain and poorly controlled diabetes, prednisone was discontinued.

Bullous pemphigoid had been diagnosed histopathologically by a prior dermatologist. Hematoxylin and eosin staining demonstrated a subepidermal separation with eosinophils within the perivascular infiltrate (Figure 2). Direct immunofluorescence was noted in a linear pattern at the dermoepidermal junction with IgG and C3. Bullous pemphigoid antigen antibodies 1 and 2 were obtained via enzyme-linked immunosorbent assay with a positive BP-1 antigen antibody of 19 U/mL (positive, >15 U/mL) and a normal BP-2 antigen antibody of less than 9 U/mL (reference range, <9 U/mL). The glucagon level was elevated at 245 pg/mL (reference range, ≤134 pg/mL).

The patient was prescribed minocycline 100 mg twice daily and niacinamide 500 mg 3 times daily. Topical treatment with clobetasol and mupirocin was continued. One month later, the patient returned with an increase in disease activity. Changes to his therapeutic regimen were deferred until after excision of the pancreatic lesion based on the decision not to start immunosuppressive therapy until the precise nature of the pancreatic lesion was determined.

The patient underwent excision of the pancreatic lesion approximately 3 months later, which proved to be a benign lymphoepithelial cyst of the pancreas. Histology of the cyst consisted of dense fibrous tissue with a squamous epithelial lining focally infiltrated by lymphocytes (Figure 3A). Immunoperoxidase staining of the cyst revealed focal linear areas of C3d staining along the basement membrane of the stratified squamous epithelium (Figure 3B).

The patient stated that his skin started to improve virtually immediately following the excision without systemic treatment for BP. On follow-up examination 3 weeks postoperatively, no bullae were observed and there was a notable decrease in erythematous crusted plaques (Figure 4).

Comment

Paraneoplastic BP has been documented; however, lymphoepithelial cysts of the pancreas in association with BP are rare. We propose that the lymphoepithelial cyst of the pancreas provided the immunologic stimulus for the development of cutaneous BP based on the observation that our patient’s condition remarkably improved with resection of the tumor.

There are fewer than 100 cases of lymphoepithelial cysts of the pancreas reported in the literature.⁸ The histologic appearance is consistent with a true cyst exhibiting a well-differentiated stratified squamous epithelium, often with keratinization, surrounded by lymphoid tissue. These tumors are most commonly seen in middle-aged men and are frequently found incidentally,^8-10 as was the case with our patient. Although histologically similar, lymphoepithelial cysts of the pancreas are considered distinct from lymphoepithelial cysts of the parotid gland or head and neck region.¹⁰ Lymphoepithelial cysts of the pancreas are unrelated to elevated glucagon levels; it is likely that our patient’s glucagon levels were associated with his history of diabetes.¹¹

In theory, any process that involves deposition of C3 should be positive for C3d on immunoperoxidase staining. Other dermatologic inflammatory conditions stain positively with C3d, such as systemic lupus erythematosus, discoid lupus erythematosus, subacute cutaneous lupus erythematosus, and dermatomysositis.¹³ The staining for these diseases correlates with the site of the associated inflammatory component seen on hematoxylin and eosin staining. The staining of C3d along the basement membrane of stratified squamous epithelium in the lymphoepithelial cyst of the pancreas seen in our patient closely resembles the staining seen in cutaneous BP.

A proposed mechanism for BP in our patient would be exposure of BP-1 antigen in the pancreatic cyst leading to antibody recognition and C3 deposition along the basement membrane in the cyst, as evidenced by C3d immunoperoxidase staining. The IgG and C3 deposition along the cutaneous basement membrane would then represent a systemic response to the antigen exposure in the cyst. Thus, the lymphoepithelial cyst provided the immunologic stimulus for the development of the cutaneous BP. This theory is based on the observation of our patient’s rapid improvement without a change in his treatment regimen immediately after surgical excision of the cyst.

Despite the plausibility of our hypothesis, several questions remain regarding the validity of our assumptions. Although sensitive for C3 deposition, C3d immunoperoxidase staining is not specific for BP. If the proposed mechanism for causation is true, one might have expected that a subepithelial cleft along the basement membrane of the pancreatic cyst would be observed, which was not seen. A repeat BP antigen antibody was not obtained, which would have been helpful in determining if there was clearance of the antibody that would have correlated with the clinical resolution of the BP lesions.

Conclusion

Our case suggests that paraneoplastic BP is a genuine entity. Indeed, the primary tumor itself may be the immunologic stimulus in the development of BP. Recalcitrant BP should raise the question of a neoplastic process that is exposing the BP antigen. If a thorough review of systems accompanied by corroborating laboratory studies suggests a neoplastic process, the suspect lesion should be further evaluated and surgically excised if clinically indicated. Further evaluation of neoplasms with advanced staining methods may aid in establishing the causative nature of tumors in the development of BP.

Acknowledgments

We are grateful to John Stanley, MD, and Aimee Payne, MD (both from Philadelphia, Pennsylvania), for theirinsights into this case.

Bullous pemphigoid (BP) is an acquired, autoimmune, subepidermal blistering disease that is more common in elderly patients.¹ An association with internal neoplasms and BP has been established; however, there is debate regarding the precise nature of the relationship.² Several gastrointestinal tract tumors have been associated with BP, including adenocarcinoma of the colon, adenosquamous cell carcinoma and adenocarcinoma of the stomach, adenocarcinoma of the rectum, and liver and bile duct malignancies.^3-5 Association with pancreatic neoplasms (eg, carcinoma of the pancreas) rarely has been reported.^5-7 We present an unusual case of a lymphoepithelial cyst of the pancreas in a patient with BP.

Case Report

A 67-year-old man presented with erythematous crusted plaques and pink scars over the chest, back, arms, and legs (Figure 1). A 1.5-cm tense bullous lesion was observed on the right knee. The patient’s medical history was notable for biopsy-proven BP of 8 months’ duration as well as diabetes mellitus and hypothyroidism. The patient was being followed by his surgeon for a 1.9-cm soft-tissue lesion in the pancreatic tail and was awaiting surgical excision at the time of the current presentation. The pancreatic lesion was discovered incidentally on magnetic resonance imaging performed following urologic concerns. At the current presentation, the patient’s medications included nifedipine, hydralazine, metoprolol, torsemide, aspirin, levothyroxine, atorvastatin, insulin lispro, and insulin glargine. He had previously been treated for BP with prednisone at a maximum dosage of 60 mg daily, clobetasol propionate cream 0.05%, and mupirocin ointment 2% without improvement. Because of substantial weight gain and poorly controlled diabetes, prednisone was discontinued.

Bullous pemphigoid had been diagnosed histopathologically by a prior dermatologist. Hematoxylin and eosin staining demonstrated a subepidermal separation with eosinophils within the perivascular infiltrate (Figure 2). Direct immunofluorescence was noted in a linear pattern at the dermoepidermal junction with IgG and C3. Bullous pemphigoid antigen antibodies 1 and 2 were obtained via enzyme-linked immunosorbent assay with a positive BP-1 antigen antibody of 19 U/mL (positive, >15 U/mL) and a normal BP-2 antigen antibody of less than 9 U/mL (reference range, <9 U/mL). The glucagon level was elevated at 245 pg/mL (reference range, ≤134 pg/mL).

The patient was prescribed minocycline 100 mg twice daily and niacinamide 500 mg 3 times daily. Topical treatment with clobetasol and mupirocin was continued. One month later, the patient returned with an increase in disease activity. Changes to his therapeutic regimen were deferred until after excision of the pancreatic lesion based on the decision not to start immunosuppressive therapy until the precise nature of the pancreatic lesion was determined.

The patient underwent excision of the pancreatic lesion approximately 3 months later, which proved to be a benign lymphoepithelial cyst of the pancreas. Histology of the cyst consisted of dense fibrous tissue with a squamous epithelial lining focally infiltrated by lymphocytes (Figure 3A). Immunoperoxidase staining of the cyst revealed focal linear areas of C3d staining along the basement membrane of the stratified squamous epithelium (Figure 3B).

The patient stated that his skin started to improve virtually immediately following the excision without systemic treatment for BP. On follow-up examination 3 weeks postoperatively, no bullae were observed and there was a notable decrease in erythematous crusted plaques (Figure 4).

Comment

Paraneoplastic BP has been documented; however, lymphoepithelial cysts of the pancreas in association with BP are rare. We propose that the lymphoepithelial cyst of the pancreas provided the immunologic stimulus for the development of cutaneous BP based on the observation that our patient’s condition remarkably improved with resection of the tumor.

There are fewer than 100 cases of lymphoepithelial cysts of the pancreas reported in the literature.⁸ The histologic appearance is consistent with a true cyst exhibiting a well-differentiated stratified squamous epithelium, often with keratinization, surrounded by lymphoid tissue. These tumors are most commonly seen in middle-aged men and are frequently found incidentally,^8-10 as was the case with our patient. Although histologically similar, lymphoepithelial cysts of the pancreas are considered distinct from lymphoepithelial cysts of the parotid gland or head and neck region.¹⁰ Lymphoepithelial cysts of the pancreas are unrelated to elevated glucagon levels; it is likely that our patient’s glucagon levels were associated with his history of diabetes.¹¹

In theory, any process that involves deposition of C3 should be positive for C3d on immunoperoxidase staining. Other dermatologic inflammatory conditions stain positively with C3d, such as systemic lupus erythematosus, discoid lupus erythematosus, subacute cutaneous lupus erythematosus, and dermatomysositis.¹³ The staining for these diseases correlates with the site of the associated inflammatory component seen on hematoxylin and eosin staining. The staining of C3d along the basement membrane of stratified squamous epithelium in the lymphoepithelial cyst of the pancreas seen in our patient closely resembles the staining seen in cutaneous BP.

A proposed mechanism for BP in our patient would be exposure of BP-1 antigen in the pancreatic cyst leading to antibody recognition and C3 deposition along the basement membrane in the cyst, as evidenced by C3d immunoperoxidase staining. The IgG and C3 deposition along the cutaneous basement membrane would then represent a systemic response to the antigen exposure in the cyst. Thus, the lymphoepithelial cyst provided the immunologic stimulus for the development of the cutaneous BP. This theory is based on the observation of our patient’s rapid improvement without a change in his treatment regimen immediately after surgical excision of the cyst.

Despite the plausibility of our hypothesis, several questions remain regarding the validity of our assumptions. Although sensitive for C3 deposition, C3d immunoperoxidase staining is not specific for BP. If the proposed mechanism for causation is true, one might have expected that a subepithelial cleft along the basement membrane of the pancreatic cyst would be observed, which was not seen. A repeat BP antigen antibody was not obtained, which would have been helpful in determining if there was clearance of the antibody that would have correlated with the clinical resolution of the BP lesions.

Conclusion

Our case suggests that paraneoplastic BP is a genuine entity. Indeed, the primary tumor itself may be the immunologic stimulus in the development of BP. Recalcitrant BP should raise the question of a neoplastic process that is exposing the BP antigen. If a thorough review of systems accompanied by corroborating laboratory studies suggests a neoplastic process, the suspect lesion should be further evaluated and surgically excised if clinically indicated. Further evaluation of neoplasms with advanced staining methods may aid in establishing the causative nature of tumors in the development of BP.

Acknowledgments

We are grateful to John Stanley, MD, and Aimee Payne, MD (both from Philadelphia, Pennsylvania), for theirinsights into this case.

Bullous pemphigoid (BP) is an acquired, autoimmune, subepidermal blistering disease that is more common in elderly patients.¹ An association with internal neoplasms and BP has been established; however, there is debate regarding the precise nature of the relationship.² Several gastrointestinal tract tumors have been associated with BP, including adenocarcinoma of the colon, adenosquamous cell carcinoma and adenocarcinoma of the stomach, adenocarcinoma of the rectum, and liver and bile duct malignancies.^3-5 Association with pancreatic neoplasms (eg, carcinoma of the pancreas) rarely has been reported.^5-7 We present an unusual case of a lymphoepithelial cyst of the pancreas in a patient with BP.

Case Report

A 67-year-old man presented with erythematous crusted plaques and pink scars over the chest, back, arms, and legs (Figure 1). A 1.5-cm tense bullous lesion was observed on the right knee. The patient’s medical history was notable for biopsy-proven BP of 8 months’ duration as well as diabetes mellitus and hypothyroidism. The patient was being followed by his surgeon for a 1.9-cm soft-tissue lesion in the pancreatic tail and was awaiting surgical excision at the time of the current presentation. The pancreatic lesion was discovered incidentally on magnetic resonance imaging performed following urologic concerns. At the current presentation, the patient’s medications included nifedipine, hydralazine, metoprolol, torsemide, aspirin, levothyroxine, atorvastatin, insulin lispro, and insulin glargine. He had previously been treated for BP with prednisone at a maximum dosage of 60 mg daily, clobetasol propionate cream 0.05%, and mupirocin ointment 2% without improvement. Because of substantial weight gain and poorly controlled diabetes, prednisone was discontinued.

Bullous pemphigoid had been diagnosed histopathologically by a prior dermatologist. Hematoxylin and eosin staining demonstrated a subepidermal separation with eosinophils within the perivascular infiltrate (Figure 2). Direct immunofluorescence was noted in a linear pattern at the dermoepidermal junction with IgG and C3. Bullous pemphigoid antigen antibodies 1 and 2 were obtained via enzyme-linked immunosorbent assay with a positive BP-1 antigen antibody of 19 U/mL (positive, >15 U/mL) and a normal BP-2 antigen antibody of less than 9 U/mL (reference range, <9 U/mL). The glucagon level was elevated at 245 pg/mL (reference range, ≤134 pg/mL).

The patient was prescribed minocycline 100 mg twice daily and niacinamide 500 mg 3 times daily. Topical treatment with clobetasol and mupirocin was continued. One month later, the patient returned with an increase in disease activity. Changes to his therapeutic regimen were deferred until after excision of the pancreatic lesion based on the decision not to start immunosuppressive therapy until the precise nature of the pancreatic lesion was determined.

The patient underwent excision of the pancreatic lesion approximately 3 months later, which proved to be a benign lymphoepithelial cyst of the pancreas. Histology of the cyst consisted of dense fibrous tissue with a squamous epithelial lining focally infiltrated by lymphocytes (Figure 3A). Immunoperoxidase staining of the cyst revealed focal linear areas of C3d staining along the basement membrane of the stratified squamous epithelium (Figure 3B).

The patient stated that his skin started to improve virtually immediately following the excision without systemic treatment for BP. On follow-up examination 3 weeks postoperatively, no bullae were observed and there was a notable decrease in erythematous crusted plaques (Figure 4).

Comment

Paraneoplastic BP has been documented; however, lymphoepithelial cysts of the pancreas in association with BP are rare. We propose that the lymphoepithelial cyst of the pancreas provided the immunologic stimulus for the development of cutaneous BP based on the observation that our patient’s condition remarkably improved with resection of the tumor.

There are fewer than 100 cases of lymphoepithelial cysts of the pancreas reported in the literature.⁸ The histologic appearance is consistent with a true cyst exhibiting a well-differentiated stratified squamous epithelium, often with keratinization, surrounded by lymphoid tissue. These tumors are most commonly seen in middle-aged men and are frequently found incidentally,^8-10 as was the case with our patient. Although histologically similar, lymphoepithelial cysts of the pancreas are considered distinct from lymphoepithelial cysts of the parotid gland or head and neck region.¹⁰ Lymphoepithelial cysts of the pancreas are unrelated to elevated glucagon levels; it is likely that our patient’s glucagon levels were associated with his history of diabetes.¹¹

In theory, any process that involves deposition of C3 should be positive for C3d on immunoperoxidase staining. Other dermatologic inflammatory conditions stain positively with C3d, such as systemic lupus erythematosus, discoid lupus erythematosus, subacute cutaneous lupus erythematosus, and dermatomysositis.¹³ The staining for these diseases correlates with the site of the associated inflammatory component seen on hematoxylin and eosin staining. The staining of C3d along the basement membrane of stratified squamous epithelium in the lymphoepithelial cyst of the pancreas seen in our patient closely resembles the staining seen in cutaneous BP.

A proposed mechanism for BP in our patient would be exposure of BP-1 antigen in the pancreatic cyst leading to antibody recognition and C3 deposition along the basement membrane in the cyst, as evidenced by C3d immunoperoxidase staining. The IgG and C3 deposition along the cutaneous basement membrane would then represent a systemic response to the antigen exposure in the cyst. Thus, the lymphoepithelial cyst provided the immunologic stimulus for the development of the cutaneous BP. This theory is based on the observation of our patient’s rapid improvement without a change in his treatment regimen immediately after surgical excision of the cyst.

Despite the plausibility of our hypothesis, several questions remain regarding the validity of our assumptions. Although sensitive for C3 deposition, C3d immunoperoxidase staining is not specific for BP. If the proposed mechanism for causation is true, one might have expected that a subepithelial cleft along the basement membrane of the pancreatic cyst would be observed, which was not seen. A repeat BP antigen antibody was not obtained, which would have been helpful in determining if there was clearance of the antibody that would have correlated with the clinical resolution of the BP lesions.

Conclusion

Our case suggests that paraneoplastic BP is a genuine entity. Indeed, the primary tumor itself may be the immunologic stimulus in the development of BP. Recalcitrant BP should raise the question of a neoplastic process that is exposing the BP antigen. If a thorough review of systems accompanied by corroborating laboratory studies suggests a neoplastic process, the suspect lesion should be further evaluated and surgically excised if clinically indicated. Further evaluation of neoplasms with advanced staining methods may aid in establishing the causative nature of tumors in the development of BP.

Acknowledgments

We are grateful to John Stanley, MD, and Aimee Payne, MD (both from Philadelphia, Pennsylvania), for theirinsights into this case.

To the Editor:

Telaprevir is a hepatitis C virus (HCV) protease inhibitor used with ribavirin and interferon for the treatment of increased viral load clearance in specific HCV genotypes. We report a case of eruptive seborrheic keratoses (SKs) secondary to telaprevir-related dermatitis.

A 65-year-old woman with a history of depression, basal cell carcinoma, and HCV presented 5 months after initiation of antiviral treatment with interferon, ribavirin, and telaprevir. Shortly after initiation of therapy, the patient developed a diffuse itch with a “pricking” sensation. The patient reported that approximately 2 months after starting treatment she developed an erythematous scaling rash that covered 75% of the body, which led to the discontinuation of telaprevir after 10 weeks of therapy; interferon and ribavirin were continued for a total of 6 months. In concert with the eczematous eruption, the patient noticed many new hyperpigmented lesions with enlargement of the few preexisting SKs. She presented to our clinic 6 weeks after the discontinuation of telaprevir for evaluation of these lesions.

On examination, several brown, hyperpigmented, stuck-on papules and plaques were noted diffusely on the body, most prominently along the frontal hairline (Figure 1). A biopsy of the right side of the forehead showed a reticulated epidermis, horn pseudocysts, and increased basilar pigment diagnostic of an SK (Figure 2).

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Telaprevir is an HCV protease inhibitor that is given in combination with interferon and ribavirin for increased clearance of genotype 1 HCV infection. Cutaneous reactions to telaprevir are seen in 41% to 61% of treated patients and include Stevens-Johnson syndrome, drug reaction with eosinophilia and systemic symptoms, sarcoidosis, pityriasis rubra pilaris–like drug eruption, and most commonly telaprevir-related dermatitis.^1-3 Telaprevir-related dermatitis accounts for up to 95% of cutaneous reactions and presents at a median of 15 days (interquartile range, 4–41 days) after initiation of therapy. Nearly 25% of cases occur in the first 4 days and 46% of cases occur within 4 weeks. It presents as an erythematous eczematous dermatitis commonly associated with pruritus in contrast to the common morbilliform drug eruption. Secondary xerosis, excoriation, and lichenification can be appreciated. With appropriate treatment, resolution occurs in a median of 44 days.¹ Treatment of the dermatitis can allow completion of the recommended 12-week course of telaprevir and involves oral antihistamines and topical corticosteroids. Severe cases may require oral corticosteroids and discontinuation of telaprevir. If the cutaneous eruption does not resolve, discontinuation of ribavirin also may be required, as it can cause a similar cutaneous eruption.⁴

To the Editor:

Telaprevir is a hepatitis C virus (HCV) protease inhibitor used with ribavirin and interferon for the treatment of increased viral load clearance in specific HCV genotypes. We report a case of eruptive seborrheic keratoses (SKs) secondary to telaprevir-related dermatitis.

A 65-year-old woman with a history of depression, basal cell carcinoma, and HCV presented 5 months after initiation of antiviral treatment with interferon, ribavirin, and telaprevir. Shortly after initiation of therapy, the patient developed a diffuse itch with a “pricking” sensation. The patient reported that approximately 2 months after starting treatment she developed an erythematous scaling rash that covered 75% of the body, which led to the discontinuation of telaprevir after 10 weeks of therapy; interferon and ribavirin were continued for a total of 6 months. In concert with the eczematous eruption, the patient noticed many new hyperpigmented lesions with enlargement of the few preexisting SKs. She presented to our clinic 6 weeks after the discontinuation of telaprevir for evaluation of these lesions.

On examination, several brown, hyperpigmented, stuck-on papules and plaques were noted diffusely on the body, most prominently along the frontal hairline (Figure 1). A biopsy of the right side of the forehead showed a reticulated epidermis, horn pseudocysts, and increased basilar pigment diagnostic of an SK (Figure 2).

[[{"attributes":{},"fields":{}}]][[{"attributes":{},"fields":{}}]]

Telaprevir is an HCV protease inhibitor that is given in combination with interferon and ribavirin for increased clearance of genotype 1 HCV infection. Cutaneous reactions to telaprevir are seen in 41% to 61% of treated patients and include Stevens-Johnson syndrome, drug reaction with eosinophilia and systemic symptoms, sarcoidosis, pityriasis rubra pilaris–like drug eruption, and most commonly telaprevir-related dermatitis.^1-3 Telaprevir-related dermatitis accounts for up to 95% of cutaneous reactions and presents at a median of 15 days (interquartile range, 4–41 days) after initiation of therapy. Nearly 25% of cases occur in the first 4 days and 46% of cases occur within 4 weeks. It presents as an erythematous eczematous dermatitis commonly associated with pruritus in contrast to the common morbilliform drug eruption. Secondary xerosis, excoriation, and lichenification can be appreciated. With appropriate treatment, resolution occurs in a median of 44 days.¹ Treatment of the dermatitis can allow completion of the recommended 12-week course of telaprevir and involves oral antihistamines and topical corticosteroids. Severe cases may require oral corticosteroids and discontinuation of telaprevir. If the cutaneous eruption does not resolve, discontinuation of ribavirin also may be required, as it can cause a similar cutaneous eruption.⁴

To the Editor:

Telaprevir is a hepatitis C virus (HCV) protease inhibitor used with ribavirin and interferon for the treatment of increased viral load clearance in specific HCV genotypes. We report a case of eruptive seborrheic keratoses (SKs) secondary to telaprevir-related dermatitis.

A 65-year-old woman with a history of depression, basal cell carcinoma, and HCV presented 5 months after initiation of antiviral treatment with interferon, ribavirin, and telaprevir. Shortly after initiation of therapy, the patient developed a diffuse itch with a “pricking” sensation. The patient reported that approximately 2 months after starting treatment she developed an erythematous scaling rash that covered 75% of the body, which led to the discontinuation of telaprevir after 10 weeks of therapy; interferon and ribavirin were continued for a total of 6 months. In concert with the eczematous eruption, the patient noticed many new hyperpigmented lesions with enlargement of the few preexisting SKs. She presented to our clinic 6 weeks after the discontinuation of telaprevir for evaluation of these lesions.

On examination, several brown, hyperpigmented, stuck-on papules and plaques were noted diffusely on the body, most prominently along the frontal hairline (Figure 1). A biopsy of the right side of the forehead showed a reticulated epidermis, horn pseudocysts, and increased basilar pigment diagnostic of an SK (Figure 2).

[[{"attributes":{},"fields":{}}]][[{"attributes":{},"fields":{}}]]

Telaprevir is an HCV protease inhibitor that is given in combination with interferon and ribavirin for increased clearance of genotype 1 HCV infection. Cutaneous reactions to telaprevir are seen in 41% to 61% of treated patients and include Stevens-Johnson syndrome, drug reaction with eosinophilia and systemic symptoms, sarcoidosis, pityriasis rubra pilaris–like drug eruption, and most commonly telaprevir-related dermatitis.^1-3 Telaprevir-related dermatitis accounts for up to 95% of cutaneous reactions and presents at a median of 15 days (interquartile range, 4–41 days) after initiation of therapy. Nearly 25% of cases occur in the first 4 days and 46% of cases occur within 4 weeks. It presents as an erythematous eczematous dermatitis commonly associated with pruritus in contrast to the common morbilliform drug eruption. Secondary xerosis, excoriation, and lichenification can be appreciated. With appropriate treatment, resolution occurs in a median of 44 days.¹ Treatment of the dermatitis can allow completion of the recommended 12-week course of telaprevir and involves oral antihistamines and topical corticosteroids. Severe cases may require oral corticosteroids and discontinuation of telaprevir. If the cutaneous eruption does not resolve, discontinuation of ribavirin also may be required, as it can cause a similar cutaneous eruption.⁴