Heba A. Abdelkader, MD

Case Report

A 70-year-old man living in Esna, Luxor, Egypt presented to the Department of Rheumatology and Rehabilitation with widespread gangrenous skin lesions associated with ulcers of 2 weeks’ duration. One year prior, the patient had an insidious onset of nocturnal fever, bilateral leg edema, and numbness and a tingling sensation in both hands. He presented some laboratory and radiologic investigations that were performed at another hospital prior to the current presentation, which revealed thrombocytopenia, mild splenomegaly, and generalized lymphadenopathy. An excisional left axillary lymph node biopsy was performed at another hospital prior to the current presentation, and the pathology report provided by the patient described a reactive, foamy, histiocyte-rich lesion, suggesting a diagnosis of hemophagocytic lymphohistiocytosis. The patient had no diabetes or hypertension and no history of deep vein thrombosis, stroke, or unintentional weight loss. No medications were taken prior to the onset of the skin lesions, and his family history was irrelevant.

General examination at the current presentation revealed a fever (temperature, 101.3 °F [38.5 °C]), a normal heart rate (90 beats per minute), normal blood pressure (120/80 mmHg), normal respiratory rate (14 breaths per minute), accentuated heart sounds, and normal vesicular breathing without adventitious sounds. He had saddle nose, loss of the outer third of the eyebrows, and marked reduction in the density of the eyelashes (madarosis). Bilateral pitting edema of the legs also was present. Neurologic examination revealed hypoesthesia in a glove-and-stocking pattern, thickened peripheral nerves, and trophic changes over both hands; however, he had normal muscle power and deep reflexes. Joint examination revealed no abnormalities. Skin examination revealed widespread, reticulated, necrotizing, purpuric lesions on the arms, legs, abdomen, and ears, some associated with gangrenous ulcerations and hemorrhagic blisters. Scattered vasculitic ulcers and gangrenous patches were seen on the fingers. A gangrenous ulcer mimicking Fournier gangrene was seen involving the scrotal skin in addition to a gangrenous lesion on the glans penis (Figure 1–3). Unaffected skin appeared smooth, shiny, and edematous and showed no nodular lesions. Peripheral pulsations were intact.

Positive findings from a wide panel of laboratory investigations included an elevated erythrocyte sedimentation rate (103 mm for the first hour [reference range, 0–22 mm]), high C-reactive protein (50.7 mg/L [reference range, up to 6 mg/L]), anemia (hemoglobin count, 7.3 g/dL [reference range, 13.5–17.5 g/dL]), thrombocytopenia (45×10³/mm³ [reference range, 150×10³/mm³), low serum albumin (2.3 g/dL [reference range, 3.4–5.4 g/dL]), elevated IgG and IgM anticardiolipin antibodies (IgG, 21.4 IgG phospholipid [GPL] units [reference range, <10 IgG phospholipid (GPL) units]; IgM, 59.4 IgM phospholipid (MPL) units [reference range, <7 IgM phospholipid (MPL) units]), positive lupus anticoagulant panel test, elevated anti-β2 glycoprotein antibodies (IgG, 17.5 µ/mL [reference range, <8 µ/mL]; IgM, 124.8 µ/mL [reference range, <8 µ/mL]), and low complement C3 (78 IU [reference range, 90–180 IU]). White blood cell count, liver and kidney functions, triglycerides, serum ferritin, and complement C4 all were normal. Hepatitis B surface antigen, hepatitis C viral antibody, HIV, antinuclear antibodies (ANA), antineutrophil cytoplasmic antibodies C and P (ANCA-C&P), and venereal disease research laboratory tests all were negative.

Nerve conduction velocity showed axonal sensory polyneuropathy. Motor nerve conduction studies for median and ulnar nerves were within normal range. Lower-limb nerves assessment was limited by the ulcerated areas and marked edema. Echocardiography was unremarkable. Arterial Doppler studies were only available for the upper limbs and were unremarkable.

A punch biopsy was taken from one of the necrotizing purpuric lesions on the legs, and histopathologic examination revealed foci of epidermal necrosis and subepidermal separation and superficial and deep perivascular and periadnexal infiltrates extending into the fat lobules. The infiltrates were mainly made up of foamy macrophages, and some contained globi (lepra cells), in addition to lymphocytes and many neutrophils with nuclear dust. Blood vessels in the superficial and deep dermis and in the subcutaneous fat showed fibrinoid necrosis in their walls with neutrophils infiltrating the walls and thrombi in the lumens (Figure 4). Modified Ziehl-Neelsen staining revealed clumps of acid-fast lepra bacilli inside vascular lumina and endothelial cell lining and within the foamy macrophages (Figure 5). Slit-skin smear examination was performed twice and yielded negative results. The slide and paraffin block of the already performed lymph node biopsy were retrieved. Examination revealed aggregates of foamy histiocytes surrounded by lymphocytes and plasma cells replacing normal lymphoid follicles. Modified Ziehl-Neelsen stain was performed, and clusters of acid-fast bacilli were detected within the foamy histiocytic infiltrate (Figure 6).

Comment

Despite a decrease in its prevalence through a World Health Organization (WHO)–empowered eradication program, leprosy still represents a health problem in endemic areas.^1,2 It is characterized by a wide range of immune responses to Mycobacterium leprae, displaying a spectrum of clinical and histopathologic manifestations that vary from the tuberculoid or paucibacillary pole with a strong cell-mediated immune response and fewer organisms to the lepromatous or multibacillary pole with weaker cell-mediated immune response and higher loads of organisms.³ In addition to its well-known cutaneous and neurologic manifestations, leprosy can present with a variety of manifestations, including constitutional symptoms, musculoskeletal manifestations, and serologic abnormalities; thus, leprosy can mimic rheumatoid arthritis, spondyloarthritis, and vasculitis—a pitfall that may result in misdiagnosis as a rheumatologic disorder.^3-7

The chronic course of leprosy can be disrupted by acute, immunologically mediated reactions known as lepra reactions, of which there are 3 types.⁸ Type I lepra reactions are cell mediated and occur mainly in patients with borderline disease, often representing an upgrade toward the tuberculoid pole; less often they represent a downgrade reaction. Nerves become painful and swollen with possible loss of function, and skin lesions become edematous and tender; sometimes arthritis develops.⁹ Type II lepra reactions, also known as erythema nodosum leprosum (ENL), occur in borderline lepromatous and lepromatous patients with a high bacillary load. They are characterized by fever, body aches, tender cutaneous/subcutaneous nodules that may ulcerate, possible bullous lesions, painful nerve swellings, swollen joints, iritis, lymphadenitis, glomerulonephritis, epididymo-orchitis, and hepatic affection. Both immune-complex and delayed hypersensitivity reactions play a role in ENL.^8,10 The third reaction is a rare aggressive type known as Lucio phenomenon or Lucio leprosy, which presents with irregular-shaped, angulated, or stellar necrotizing purpuric lesions (hemorrhagic infacrtions) developing mainly on the extremities. The lesions evolve into ulcers that heal with atrophic scarring.^2,11 Lucio phenomenon develops as a result of thrombotic vascular occlusion secondary to massive invasion of vascular endothelial cells by lepra bacilli.^2,11-14 Involvement of the scrotal skin, such as in our patient, is rare.

Lucio phenomenon mainly is seen in Mexico and Central America, and few cases have been documented in Cuba, South America, the United States, India, Polynesia, South Africa, and Southeast Asia.^15-17 It specifically occurs in patients with untreated, diffuse, nonnodular lepromatous leprosy (pure and primitive diffuse lepromatous leprosy (DLL)/diffuse leprosy of Lucio and Latapí). This type of leprosy was first described by Lucio and Alvarado¹⁸ in 1852 as a distinct form of lepromatous leprosy characterized by widespread and dense infiltration of the whole skin by lepra bacilli without the typical nodular lesions of leprosy, rendering its diagnosis challenging, especially in sporadic cases. Other manifestations of DLL include complete alopecia of the eyebrows and eyelashes, destructive rhinitis, and areas of anhidrosis and dyesthesia.²

Latapí and Chévez-Zomora¹⁹ defined Lucio phenomenon in 1948 as a form of histopathologic vasculitis restricted to patients with DLL. Histopathologically, in addition to the infiltration of the skin with acid-fast bacilli–laden foamy histiocytes, lesions of Lucio phenomenon show features of necrotizing (leukocytoclastic) vasculitis with fibrinoid necrosis²⁰ or vascular thrombi with minimal perivascular lymphocytic infiltrate and no evidence of vasculitis.¹¹ Medium to large vessels in the deep dermis and subcutaneous tissue show infiltration of their walls with a large number of macrophages laden with acid-fast bacilli.¹¹ Cases with histopathologic features mimicking antiphospholipid syndrome with endothelial cell proliferation, thrombosis, and mild mononuclear cell infiltrate also may be seen.²⁰ In all cases, ischemic epidermal necrosis is seen, as well as acid-fast bacilli, both singly and in clusters (globi) within endothelial cells and inside blood vessel lumina.

Although Lucio phenomenon initially was thought to be immune-complex mediated like ENL, it has been suggested that the main trigger is thrombotic vascular occlusion secondary to massive invasion of the vascular endothelial cells by the lepra bacilli, resulting in necrosis.¹⁴ Bacterial lipopolysaccharides promote the release of IL-1 and tumor necrosis factor α, which in turn stimulate the production of prostaglandins, IL-6, and coagulation factor III, leading to vascular thrombosis and tissue necrosis.^21,22 Moreover, antiphospholipid antibodies, which have been found to be induced in response to certain infectious agents in genetically predisposed individuals,²³ have been reported in patients with leprosy, mainly in association with lepromatous leprosy. The reported prevalence of anticardiolipin antibodies ranged from 37% to 98%, whereas anti-β2-glycoprotein I antibodies ranged from 3% to 19%, and antiprothrombin antibodies ranged from 6% to 45%.^24,25 Antiphospholipid antibodies have been reported to play a role in the pathogenesis of Lucio phenomenon.^11,13,15,26 Our case supports this hypothesis with positive anticardiolipin antibodies, anti-β2 glycoprotein antibodies, and positive lupus anticoagulant.

In accordance with Curi et al,² who reported 5 cases of DLL with Lucio phenomenon, our patient showed a similar presentation with positive inflammatory markers in association with a negative autoimmune profile (ANA, ANCA-C&P) and negative venereal disease research laboratory test. It is important to mention that a positive autoimmune profile (ANA, ANCA-C&P) can be present in leprotic patients, causing possible diagnostic confusion with collagen diseases.^27,28

An interesting finding in our case was the negative slit-skin smear results. Although the specificity of slit-skin smear is 100%, as it directly demonstrates the presence of acid-fast bacilli,²⁹ its sensitivity is low and varies from 10% to 50%.³⁰ The detection of acid-fast bacilli in tissue sections is reported to be a better method for confirming the diagnosis of leprosy.³¹

The provisional impression of hemophagocytic lymphohistiocytosis in the lymph node biopsy in our patient was excluded upon detection of acid-fast bacilli in the foamy histiocytes infiltrating the lymph node; moreover, the normal serum lipids and serum ferritin argued against this diagnosis.³² Leprosy tends to involve the lymph nodes, particularly in borderline, borderline lepromatous, and lepromatous forms.³³ The incidence of lymph node involvement accompanied by skin lesions with the presence of acid-fast bacilli in the lymph nodes is 92.2%.³⁴

Our patient showed an excellent response to antileprotic treatment, which was administered according to the WHO multidrug therapy guidelines for multibacillary leprosy,³⁵ combined with low-dose prednisolone, acetylsalicylic acid, and anticoagulant treatment. Thalidomide and high-dose prednisolone (60 mg/d) combined with antileprotic treatment also have been reported to be successful in managing recurrent infarctions in leprosy.³⁶ The Fournier-like gangrenous ulcer of the scrotum was managed by surgical debridement and vacuum therapy.

It is noteworthy that the WHO elimination goal for leprosy was to reduce the prevalence to less than 1 case per 10,000 population. Egypt is among the first countries in North Africa and the Middle East regions to achieve this target supervised by the National Leprosy Control Program as early as 1994; this was further reduced to 0.33 cases per 10,000 population in 2004, and reduced again in 2009; however, certain foci showed a prevalence rate more than the elimination target, particularly in the cities of Qena (1.12) and Sohag (2.47).³⁷ Esna, where our patient is from, is an endemic area in Egypt.³⁸

Conclusion

Leprosy is a great mimicker of many connective tissue diseases, including vasculitis. Antiphospholipid antibodies are involved in Lucio phenomenon. Recognition of Lucio phenomenon is important to initiate prompt treatment and avoid morbidity and mortality. We report a rare case of diffuse nonnodular lepromatous leprosy in Egypt in which Lucio phenomenon was the first diagnostic presentation. Scrotal involvement with Lucio phenomenon was not previously reported in any case of Lucio leprosy.

Case Report

A 70-year-old man living in Esna, Luxor, Egypt presented to the Department of Rheumatology and Rehabilitation with widespread gangrenous skin lesions associated with ulcers of 2 weeks’ duration. One year prior, the patient had an insidious onset of nocturnal fever, bilateral leg edema, and numbness and a tingling sensation in both hands. He presented some laboratory and radiologic investigations that were performed at another hospital prior to the current presentation, which revealed thrombocytopenia, mild splenomegaly, and generalized lymphadenopathy. An excisional left axillary lymph node biopsy was performed at another hospital prior to the current presentation, and the pathology report provided by the patient described a reactive, foamy, histiocyte-rich lesion, suggesting a diagnosis of hemophagocytic lymphohistiocytosis. The patient had no diabetes or hypertension and no history of deep vein thrombosis, stroke, or unintentional weight loss. No medications were taken prior to the onset of the skin lesions, and his family history was irrelevant.

General examination at the current presentation revealed a fever (temperature, 101.3 °F [38.5 °C]), a normal heart rate (90 beats per minute), normal blood pressure (120/80 mmHg), normal respiratory rate (14 breaths per minute), accentuated heart sounds, and normal vesicular breathing without adventitious sounds. He had saddle nose, loss of the outer third of the eyebrows, and marked reduction in the density of the eyelashes (madarosis). Bilateral pitting edema of the legs also was present. Neurologic examination revealed hypoesthesia in a glove-and-stocking pattern, thickened peripheral nerves, and trophic changes over both hands; however, he had normal muscle power and deep reflexes. Joint examination revealed no abnormalities. Skin examination revealed widespread, reticulated, necrotizing, purpuric lesions on the arms, legs, abdomen, and ears, some associated with gangrenous ulcerations and hemorrhagic blisters. Scattered vasculitic ulcers and gangrenous patches were seen on the fingers. A gangrenous ulcer mimicking Fournier gangrene was seen involving the scrotal skin in addition to a gangrenous lesion on the glans penis (Figure 1–3). Unaffected skin appeared smooth, shiny, and edematous and showed no nodular lesions. Peripheral pulsations were intact.

Positive findings from a wide panel of laboratory investigations included an elevated erythrocyte sedimentation rate (103 mm for the first hour [reference range, 0–22 mm]), high C-reactive protein (50.7 mg/L [reference range, up to 6 mg/L]), anemia (hemoglobin count, 7.3 g/dL [reference range, 13.5–17.5 g/dL]), thrombocytopenia (45×10³/mm³ [reference range, 150×10³/mm³), low serum albumin (2.3 g/dL [reference range, 3.4–5.4 g/dL]), elevated IgG and IgM anticardiolipin antibodies (IgG, 21.4 IgG phospholipid [GPL] units [reference range, <10 IgG phospholipid (GPL) units]; IgM, 59.4 IgM phospholipid (MPL) units [reference range, <7 IgM phospholipid (MPL) units]), positive lupus anticoagulant panel test, elevated anti-β2 glycoprotein antibodies (IgG, 17.5 µ/mL [reference range, <8 µ/mL]; IgM, 124.8 µ/mL [reference range, <8 µ/mL]), and low complement C3 (78 IU [reference range, 90–180 IU]). White blood cell count, liver and kidney functions, triglycerides, serum ferritin, and complement C4 all were normal. Hepatitis B surface antigen, hepatitis C viral antibody, HIV, antinuclear antibodies (ANA), antineutrophil cytoplasmic antibodies C and P (ANCA-C&P), and venereal disease research laboratory tests all were negative.

Nerve conduction velocity showed axonal sensory polyneuropathy. Motor nerve conduction studies for median and ulnar nerves were within normal range. Lower-limb nerves assessment was limited by the ulcerated areas and marked edema. Echocardiography was unremarkable. Arterial Doppler studies were only available for the upper limbs and were unremarkable.

A punch biopsy was taken from one of the necrotizing purpuric lesions on the legs, and histopathologic examination revealed foci of epidermal necrosis and subepidermal separation and superficial and deep perivascular and periadnexal infiltrates extending into the fat lobules. The infiltrates were mainly made up of foamy macrophages, and some contained globi (lepra cells), in addition to lymphocytes and many neutrophils with nuclear dust. Blood vessels in the superficial and deep dermis and in the subcutaneous fat showed fibrinoid necrosis in their walls with neutrophils infiltrating the walls and thrombi in the lumens (Figure 4). Modified Ziehl-Neelsen staining revealed clumps of acid-fast lepra bacilli inside vascular lumina and endothelial cell lining and within the foamy macrophages (Figure 5). Slit-skin smear examination was performed twice and yielded negative results. The slide and paraffin block of the already performed lymph node biopsy were retrieved. Examination revealed aggregates of foamy histiocytes surrounded by lymphocytes and plasma cells replacing normal lymphoid follicles. Modified Ziehl-Neelsen stain was performed, and clusters of acid-fast bacilli were detected within the foamy histiocytic infiltrate (Figure 6).

Comment

Despite a decrease in its prevalence through a World Health Organization (WHO)–empowered eradication program, leprosy still represents a health problem in endemic areas.^1,2 It is characterized by a wide range of immune responses to Mycobacterium leprae, displaying a spectrum of clinical and histopathologic manifestations that vary from the tuberculoid or paucibacillary pole with a strong cell-mediated immune response and fewer organisms to the lepromatous or multibacillary pole with weaker cell-mediated immune response and higher loads of organisms.³ In addition to its well-known cutaneous and neurologic manifestations, leprosy can present with a variety of manifestations, including constitutional symptoms, musculoskeletal manifestations, and serologic abnormalities; thus, leprosy can mimic rheumatoid arthritis, spondyloarthritis, and vasculitis—a pitfall that may result in misdiagnosis as a rheumatologic disorder.^3-7

The chronic course of leprosy can be disrupted by acute, immunologically mediated reactions known as lepra reactions, of which there are 3 types.⁸ Type I lepra reactions are cell mediated and occur mainly in patients with borderline disease, often representing an upgrade toward the tuberculoid pole; less often they represent a downgrade reaction. Nerves become painful and swollen with possible loss of function, and skin lesions become edematous and tender; sometimes arthritis develops.⁹ Type II lepra reactions, also known as erythema nodosum leprosum (ENL), occur in borderline lepromatous and lepromatous patients with a high bacillary load. They are characterized by fever, body aches, tender cutaneous/subcutaneous nodules that may ulcerate, possible bullous lesions, painful nerve swellings, swollen joints, iritis, lymphadenitis, glomerulonephritis, epididymo-orchitis, and hepatic affection. Both immune-complex and delayed hypersensitivity reactions play a role in ENL.^8,10 The third reaction is a rare aggressive type known as Lucio phenomenon or Lucio leprosy, which presents with irregular-shaped, angulated, or stellar necrotizing purpuric lesions (hemorrhagic infacrtions) developing mainly on the extremities. The lesions evolve into ulcers that heal with atrophic scarring.^2,11 Lucio phenomenon develops as a result of thrombotic vascular occlusion secondary to massive invasion of vascular endothelial cells by lepra bacilli.^2,11-14 Involvement of the scrotal skin, such as in our patient, is rare.

Lucio phenomenon mainly is seen in Mexico and Central America, and few cases have been documented in Cuba, South America, the United States, India, Polynesia, South Africa, and Southeast Asia.^15-17 It specifically occurs in patients with untreated, diffuse, nonnodular lepromatous leprosy (pure and primitive diffuse lepromatous leprosy (DLL)/diffuse leprosy of Lucio and Latapí). This type of leprosy was first described by Lucio and Alvarado¹⁸ in 1852 as a distinct form of lepromatous leprosy characterized by widespread and dense infiltration of the whole skin by lepra bacilli without the typical nodular lesions of leprosy, rendering its diagnosis challenging, especially in sporadic cases. Other manifestations of DLL include complete alopecia of the eyebrows and eyelashes, destructive rhinitis, and areas of anhidrosis and dyesthesia.²

Latapí and Chévez-Zomora¹⁹ defined Lucio phenomenon in 1948 as a form of histopathologic vasculitis restricted to patients with DLL. Histopathologically, in addition to the infiltration of the skin with acid-fast bacilli–laden foamy histiocytes, lesions of Lucio phenomenon show features of necrotizing (leukocytoclastic) vasculitis with fibrinoid necrosis²⁰ or vascular thrombi with minimal perivascular lymphocytic infiltrate and no evidence of vasculitis.¹¹ Medium to large vessels in the deep dermis and subcutaneous tissue show infiltration of their walls with a large number of macrophages laden with acid-fast bacilli.¹¹ Cases with histopathologic features mimicking antiphospholipid syndrome with endothelial cell proliferation, thrombosis, and mild mononuclear cell infiltrate also may be seen.²⁰ In all cases, ischemic epidermal necrosis is seen, as well as acid-fast bacilli, both singly and in clusters (globi) within endothelial cells and inside blood vessel lumina.

Although Lucio phenomenon initially was thought to be immune-complex mediated like ENL, it has been suggested that the main trigger is thrombotic vascular occlusion secondary to massive invasion of the vascular endothelial cells by the lepra bacilli, resulting in necrosis.¹⁴ Bacterial lipopolysaccharides promote the release of IL-1 and tumor necrosis factor α, which in turn stimulate the production of prostaglandins, IL-6, and coagulation factor III, leading to vascular thrombosis and tissue necrosis.^21,22 Moreover, antiphospholipid antibodies, which have been found to be induced in response to certain infectious agents in genetically predisposed individuals,²³ have been reported in patients with leprosy, mainly in association with lepromatous leprosy. The reported prevalence of anticardiolipin antibodies ranged from 37% to 98%, whereas anti-β2-glycoprotein I antibodies ranged from 3% to 19%, and antiprothrombin antibodies ranged from 6% to 45%.^24,25 Antiphospholipid antibodies have been reported to play a role in the pathogenesis of Lucio phenomenon.^11,13,15,26 Our case supports this hypothesis with positive anticardiolipin antibodies, anti-β2 glycoprotein antibodies, and positive lupus anticoagulant.

In accordance with Curi et al,² who reported 5 cases of DLL with Lucio phenomenon, our patient showed a similar presentation with positive inflammatory markers in association with a negative autoimmune profile (ANA, ANCA-C&P) and negative venereal disease research laboratory test. It is important to mention that a positive autoimmune profile (ANA, ANCA-C&P) can be present in leprotic patients, causing possible diagnostic confusion with collagen diseases.^27,28

An interesting finding in our case was the negative slit-skin smear results. Although the specificity of slit-skin smear is 100%, as it directly demonstrates the presence of acid-fast bacilli,²⁹ its sensitivity is low and varies from 10% to 50%.³⁰ The detection of acid-fast bacilli in tissue sections is reported to be a better method for confirming the diagnosis of leprosy.³¹

The provisional impression of hemophagocytic lymphohistiocytosis in the lymph node biopsy in our patient was excluded upon detection of acid-fast bacilli in the foamy histiocytes infiltrating the lymph node; moreover, the normal serum lipids and serum ferritin argued against this diagnosis.³² Leprosy tends to involve the lymph nodes, particularly in borderline, borderline lepromatous, and lepromatous forms.³³ The incidence of lymph node involvement accompanied by skin lesions with the presence of acid-fast bacilli in the lymph nodes is 92.2%.³⁴

Our patient showed an excellent response to antileprotic treatment, which was administered according to the WHO multidrug therapy guidelines for multibacillary leprosy,³⁵ combined with low-dose prednisolone, acetylsalicylic acid, and anticoagulant treatment. Thalidomide and high-dose prednisolone (60 mg/d) combined with antileprotic treatment also have been reported to be successful in managing recurrent infarctions in leprosy.³⁶ The Fournier-like gangrenous ulcer of the scrotum was managed by surgical debridement and vacuum therapy.

It is noteworthy that the WHO elimination goal for leprosy was to reduce the prevalence to less than 1 case per 10,000 population. Egypt is among the first countries in North Africa and the Middle East regions to achieve this target supervised by the National Leprosy Control Program as early as 1994; this was further reduced to 0.33 cases per 10,000 population in 2004, and reduced again in 2009; however, certain foci showed a prevalence rate more than the elimination target, particularly in the cities of Qena (1.12) and Sohag (2.47).³⁷ Esna, where our patient is from, is an endemic area in Egypt.³⁸

Conclusion

Leprosy is a great mimicker of many connective tissue diseases, including vasculitis. Antiphospholipid antibodies are involved in Lucio phenomenon. Recognition of Lucio phenomenon is important to initiate prompt treatment and avoid morbidity and mortality. We report a rare case of diffuse nonnodular lepromatous leprosy in Egypt in which Lucio phenomenon was the first diagnostic presentation. Scrotal involvement with Lucio phenomenon was not previously reported in any case of Lucio leprosy.

Case Report

A 70-year-old man living in Esna, Luxor, Egypt presented to the Department of Rheumatology and Rehabilitation with widespread gangrenous skin lesions associated with ulcers of 2 weeks’ duration. One year prior, the patient had an insidious onset of nocturnal fever, bilateral leg edema, and numbness and a tingling sensation in both hands. He presented some laboratory and radiologic investigations that were performed at another hospital prior to the current presentation, which revealed thrombocytopenia, mild splenomegaly, and generalized lymphadenopathy. An excisional left axillary lymph node biopsy was performed at another hospital prior to the current presentation, and the pathology report provided by the patient described a reactive, foamy, histiocyte-rich lesion, suggesting a diagnosis of hemophagocytic lymphohistiocytosis. The patient had no diabetes or hypertension and no history of deep vein thrombosis, stroke, or unintentional weight loss. No medications were taken prior to the onset of the skin lesions, and his family history was irrelevant.

General examination at the current presentation revealed a fever (temperature, 101.3 °F [38.5 °C]), a normal heart rate (90 beats per minute), normal blood pressure (120/80 mmHg), normal respiratory rate (14 breaths per minute), accentuated heart sounds, and normal vesicular breathing without adventitious sounds. He had saddle nose, loss of the outer third of the eyebrows, and marked reduction in the density of the eyelashes (madarosis). Bilateral pitting edema of the legs also was present. Neurologic examination revealed hypoesthesia in a glove-and-stocking pattern, thickened peripheral nerves, and trophic changes over both hands; however, he had normal muscle power and deep reflexes. Joint examination revealed no abnormalities. Skin examination revealed widespread, reticulated, necrotizing, purpuric lesions on the arms, legs, abdomen, and ears, some associated with gangrenous ulcerations and hemorrhagic blisters. Scattered vasculitic ulcers and gangrenous patches were seen on the fingers. A gangrenous ulcer mimicking Fournier gangrene was seen involving the scrotal skin in addition to a gangrenous lesion on the glans penis (Figure 1–3). Unaffected skin appeared smooth, shiny, and edematous and showed no nodular lesions. Peripheral pulsations were intact.

Positive findings from a wide panel of laboratory investigations included an elevated erythrocyte sedimentation rate (103 mm for the first hour [reference range, 0–22 mm]), high C-reactive protein (50.7 mg/L [reference range, up to 6 mg/L]), anemia (hemoglobin count, 7.3 g/dL [reference range, 13.5–17.5 g/dL]), thrombocytopenia (45×10³/mm³ [reference range, 150×10³/mm³), low serum albumin (2.3 g/dL [reference range, 3.4–5.4 g/dL]), elevated IgG and IgM anticardiolipin antibodies (IgG, 21.4 IgG phospholipid [GPL] units [reference range, <10 IgG phospholipid (GPL) units]; IgM, 59.4 IgM phospholipid (MPL) units [reference range, <7 IgM phospholipid (MPL) units]), positive lupus anticoagulant panel test, elevated anti-β2 glycoprotein antibodies (IgG, 17.5 µ/mL [reference range, <8 µ/mL]; IgM, 124.8 µ/mL [reference range, <8 µ/mL]), and low complement C3 (78 IU [reference range, 90–180 IU]). White blood cell count, liver and kidney functions, triglycerides, serum ferritin, and complement C4 all were normal. Hepatitis B surface antigen, hepatitis C viral antibody, HIV, antinuclear antibodies (ANA), antineutrophil cytoplasmic antibodies C and P (ANCA-C&P), and venereal disease research laboratory tests all were negative.

Nerve conduction velocity showed axonal sensory polyneuropathy. Motor nerve conduction studies for median and ulnar nerves were within normal range. Lower-limb nerves assessment was limited by the ulcerated areas and marked edema. Echocardiography was unremarkable. Arterial Doppler studies were only available for the upper limbs and were unremarkable.

A punch biopsy was taken from one of the necrotizing purpuric lesions on the legs, and histopathologic examination revealed foci of epidermal necrosis and subepidermal separation and superficial and deep perivascular and periadnexal infiltrates extending into the fat lobules. The infiltrates were mainly made up of foamy macrophages, and some contained globi (lepra cells), in addition to lymphocytes and many neutrophils with nuclear dust. Blood vessels in the superficial and deep dermis and in the subcutaneous fat showed fibrinoid necrosis in their walls with neutrophils infiltrating the walls and thrombi in the lumens (Figure 4). Modified Ziehl-Neelsen staining revealed clumps of acid-fast lepra bacilli inside vascular lumina and endothelial cell lining and within the foamy macrophages (Figure 5). Slit-skin smear examination was performed twice and yielded negative results. The slide and paraffin block of the already performed lymph node biopsy were retrieved. Examination revealed aggregates of foamy histiocytes surrounded by lymphocytes and plasma cells replacing normal lymphoid follicles. Modified Ziehl-Neelsen stain was performed, and clusters of acid-fast bacilli were detected within the foamy histiocytic infiltrate (Figure 6).

Comment

Despite a decrease in its prevalence through a World Health Organization (WHO)–empowered eradication program, leprosy still represents a health problem in endemic areas.^1,2 It is characterized by a wide range of immune responses to Mycobacterium leprae, displaying a spectrum of clinical and histopathologic manifestations that vary from the tuberculoid or paucibacillary pole with a strong cell-mediated immune response and fewer organisms to the lepromatous or multibacillary pole with weaker cell-mediated immune response and higher loads of organisms.³ In addition to its well-known cutaneous and neurologic manifestations, leprosy can present with a variety of manifestations, including constitutional symptoms, musculoskeletal manifestations, and serologic abnormalities; thus, leprosy can mimic rheumatoid arthritis, spondyloarthritis, and vasculitis—a pitfall that may result in misdiagnosis as a rheumatologic disorder.^3-7

The chronic course of leprosy can be disrupted by acute, immunologically mediated reactions known as lepra reactions, of which there are 3 types.⁸ Type I lepra reactions are cell mediated and occur mainly in patients with borderline disease, often representing an upgrade toward the tuberculoid pole; less often they represent a downgrade reaction. Nerves become painful and swollen with possible loss of function, and skin lesions become edematous and tender; sometimes arthritis develops.⁹ Type II lepra reactions, also known as erythema nodosum leprosum (ENL), occur in borderline lepromatous and lepromatous patients with a high bacillary load. They are characterized by fever, body aches, tender cutaneous/subcutaneous nodules that may ulcerate, possible bullous lesions, painful nerve swellings, swollen joints, iritis, lymphadenitis, glomerulonephritis, epididymo-orchitis, and hepatic affection. Both immune-complex and delayed hypersensitivity reactions play a role in ENL.^8,10 The third reaction is a rare aggressive type known as Lucio phenomenon or Lucio leprosy, which presents with irregular-shaped, angulated, or stellar necrotizing purpuric lesions (hemorrhagic infacrtions) developing mainly on the extremities. The lesions evolve into ulcers that heal with atrophic scarring.^2,11 Lucio phenomenon develops as a result of thrombotic vascular occlusion secondary to massive invasion of vascular endothelial cells by lepra bacilli.^2,11-14 Involvement of the scrotal skin, such as in our patient, is rare.

Lucio phenomenon mainly is seen in Mexico and Central America, and few cases have been documented in Cuba, South America, the United States, India, Polynesia, South Africa, and Southeast Asia.^15-17 It specifically occurs in patients with untreated, diffuse, nonnodular lepromatous leprosy (pure and primitive diffuse lepromatous leprosy (DLL)/diffuse leprosy of Lucio and Latapí). This type of leprosy was first described by Lucio and Alvarado¹⁸ in 1852 as a distinct form of lepromatous leprosy characterized by widespread and dense infiltration of the whole skin by lepra bacilli without the typical nodular lesions of leprosy, rendering its diagnosis challenging, especially in sporadic cases. Other manifestations of DLL include complete alopecia of the eyebrows and eyelashes, destructive rhinitis, and areas of anhidrosis and dyesthesia.²

Latapí and Chévez-Zomora¹⁹ defined Lucio phenomenon in 1948 as a form of histopathologic vasculitis restricted to patients with DLL. Histopathologically, in addition to the infiltration of the skin with acid-fast bacilli–laden foamy histiocytes, lesions of Lucio phenomenon show features of necrotizing (leukocytoclastic) vasculitis with fibrinoid necrosis²⁰ or vascular thrombi with minimal perivascular lymphocytic infiltrate and no evidence of vasculitis.¹¹ Medium to large vessels in the deep dermis and subcutaneous tissue show infiltration of their walls with a large number of macrophages laden with acid-fast bacilli.¹¹ Cases with histopathologic features mimicking antiphospholipid syndrome with endothelial cell proliferation, thrombosis, and mild mononuclear cell infiltrate also may be seen.²⁰ In all cases, ischemic epidermal necrosis is seen, as well as acid-fast bacilli, both singly and in clusters (globi) within endothelial cells and inside blood vessel lumina.

Although Lucio phenomenon initially was thought to be immune-complex mediated like ENL, it has been suggested that the main trigger is thrombotic vascular occlusion secondary to massive invasion of the vascular endothelial cells by the lepra bacilli, resulting in necrosis.¹⁴ Bacterial lipopolysaccharides promote the release of IL-1 and tumor necrosis factor α, which in turn stimulate the production of prostaglandins, IL-6, and coagulation factor III, leading to vascular thrombosis and tissue necrosis.^21,22 Moreover, antiphospholipid antibodies, which have been found to be induced in response to certain infectious agents in genetically predisposed individuals,²³ have been reported in patients with leprosy, mainly in association with lepromatous leprosy. The reported prevalence of anticardiolipin antibodies ranged from 37% to 98%, whereas anti-β2-glycoprotein I antibodies ranged from 3% to 19%, and antiprothrombin antibodies ranged from 6% to 45%.^24,25 Antiphospholipid antibodies have been reported to play a role in the pathogenesis of Lucio phenomenon.^11,13,15,26 Our case supports this hypothesis with positive anticardiolipin antibodies, anti-β2 glycoprotein antibodies, and positive lupus anticoagulant.

In accordance with Curi et al,² who reported 5 cases of DLL with Lucio phenomenon, our patient showed a similar presentation with positive inflammatory markers in association with a negative autoimmune profile (ANA, ANCA-C&P) and negative venereal disease research laboratory test. It is important to mention that a positive autoimmune profile (ANA, ANCA-C&P) can be present in leprotic patients, causing possible diagnostic confusion with collagen diseases.^27,28

An interesting finding in our case was the negative slit-skin smear results. Although the specificity of slit-skin smear is 100%, as it directly demonstrates the presence of acid-fast bacilli,²⁹ its sensitivity is low and varies from 10% to 50%.³⁰ The detection of acid-fast bacilli in tissue sections is reported to be a better method for confirming the diagnosis of leprosy.³¹

The provisional impression of hemophagocytic lymphohistiocytosis in the lymph node biopsy in our patient was excluded upon detection of acid-fast bacilli in the foamy histiocytes infiltrating the lymph node; moreover, the normal serum lipids and serum ferritin argued against this diagnosis.³² Leprosy tends to involve the lymph nodes, particularly in borderline, borderline lepromatous, and lepromatous forms.³³ The incidence of lymph node involvement accompanied by skin lesions with the presence of acid-fast bacilli in the lymph nodes is 92.2%.³⁴

Our patient showed an excellent response to antileprotic treatment, which was administered according to the WHO multidrug therapy guidelines for multibacillary leprosy,³⁵ combined with low-dose prednisolone, acetylsalicylic acid, and anticoagulant treatment. Thalidomide and high-dose prednisolone (60 mg/d) combined with antileprotic treatment also have been reported to be successful in managing recurrent infarctions in leprosy.³⁶ The Fournier-like gangrenous ulcer of the scrotum was managed by surgical debridement and vacuum therapy.

It is noteworthy that the WHO elimination goal for leprosy was to reduce the prevalence to less than 1 case per 10,000 population. Egypt is among the first countries in North Africa and the Middle East regions to achieve this target supervised by the National Leprosy Control Program as early as 1994; this was further reduced to 0.33 cases per 10,000 population in 2004, and reduced again in 2009; however, certain foci showed a prevalence rate more than the elimination target, particularly in the cities of Qena (1.12) and Sohag (2.47).³⁷ Esna, where our patient is from, is an endemic area in Egypt.³⁸

Conclusion

Leprosy is a great mimicker of many connective tissue diseases, including vasculitis. Antiphospholipid antibodies are involved in Lucio phenomenon. Recognition of Lucio phenomenon is important to initiate prompt treatment and avoid morbidity and mortality. We report a rare case of diffuse nonnodular lepromatous leprosy in Egypt in which Lucio phenomenon was the first diagnostic presentation. Scrotal involvement with Lucio phenomenon was not previously reported in any case of Lucio leprosy.

The Diagnosis: Unilateral Dermatomal Trichoepithelioma  

Adnexal lesions presenting with a linear and/or dermatomal pattern rarely have been reported. Bolognia et al¹ performed a comprehensive review of Blaschko lines and skin conditions that follow such a pattern. The authors found that adnexal-related lesions included linear nevus comedonicus, linear basal cell nevus with comedones (linear basaloid follicular hamartoma), unilateral nevoid basal cell carcinoma (BCC), linear trichoepithelioma, linear trichodiscoma, linear hamartoma of the follicular infundibulum, nevus sebaceous, syringocystadenoma papilliferum, porokeratotic eccrine ostial and dermal duct nevus, linear eccrine poroma, linear spiradenoma, linear syringoma, and linear eccrine syringofibroadenoma.¹  

Trichoepithelioma is a hair follicle-related neoplastic lesion presenting most commonly as the autosomal-dominant multiple familial type with lesions mainly centered on the face. Initial genetic studies associated the disease with loss of heterozygosity in the 9p21 region and further studies identified mutations in the CYLD (cylindromatosis [turban tumor syndrome]) gene on chromosome 16q12-q13.^2,3 Unilateral, linear, and dermatomal forms of trichoepithelioma rarely are reported. In 1986, Geffner et al⁴ reported a case of linear and dermatomal trichoepithelioma in a 10-year-old girl. In addition to discrete solitary lesions affecting the face, she developed lesions on the left shoulder, left side of the trunk, and left lower leg following dermatomal distribution. In 2006, 2 cases of dermatomal trichoepitheliomas affecting the face in children, as in our case, were reported.^5,6 Another case involving the neck was reported in 2016.⁷ Although classic multiple familial trichoepithelioma can be part of conditions such as Brooke-Spiegler⁸ and Rombo syndromes,⁹ no syndromal association has been reported thus far with the unilateral, linear, or dermatomal variants.  

Our case showed typical histopathologic features of trichoepithelioma, including discrete islands of basaloid cells in the dermis set in a conspicuous fibroblastic stroma. Focal connection with the epidermis was present. Most of the islands showed peripheral palisading and horn cysts lined by eosinophilic cells. The fibroblastic component was tightly adherent to the epithelial component, and only stromal clefts were detected. Papillary mesenchymal bodies also were detected as oval aggregates of fibroblastic cells invaginating into epithelial islands to form hair papillae. 

Histopathologically, the 2 most important differential diagnoses of trichoepithelioma include BCC and basaloid follicular hamartoma. In differentiating BCC from trichoepithelioma, the presence of dense fibroblastic stroma and papillary mesenchymal bodies characterize trichoepithelioma, while a fibromucinous stroma with mucinous retraction artifacts and clefting between the basaloid islands and the stroma characterize BCC (Figure 1).¹⁰ Immunohistochemical studies using antibodies against Bcl-2, CD34, CD10, androgen receptor, Ki-67, cytokeratin 19, and PHLDA1 (pleckstrin homologylike domain family A member 1) have reportedly been utilized to differentiate trichoepithelioma from BCC.^11,12 Basaloid follicular hamartoma is characterized by thin anastomosing strands and branching cords of undifferentiated basaloid cells that replace or associate hair follicles in a latticelike pattern (Figure 2). The strands usually are vertically oriented perpendicular to the epidermis. Peripheral palisading is possible, and the basaloid strands are surrounded with cellular connective tissue stroma.¹³ Tumor islands in eccrine poroma show broad connections with the epidermis and are composed of poroid cells that show evident ductal differentiation with eosinophilic cuticles (Figure 3).¹⁴ Spiradenoma is characterized by capsulated deep-seated tumorous nodules not connected with the epidermis and composed of light and dark cells with ductal differentiation and vascular stroma (Figure 4). Scattered lymphocytes within the tumor lobules and in the stroma also are seen. Eosinophilic hyaline globules rarely can be present.¹⁵ 

Many pathologists consider trichoepithelioma as the superficial variant of trichoblastoma. According to the recent World Health Organization classification of benign tumors with follicular differentiation, trichoepithelioma is considered synonymous with trichoblastoma.¹⁶ 

Trichoepitheliomas are benign tumors, and therapy is mainly directed at removal for cosmetic purposes. Several methods of removal are available including electrocautery, laser therapy, and surgery. Awareness of the possible dermatomal distribution of hair follicle and other adnexal-related conditions is important, and such lesions should be thought of in the differential diagnosis of unilateral and/or dermatomal lesions.

The Diagnosis: Unilateral Dermatomal Trichoepithelioma  

Adnexal lesions presenting with a linear and/or dermatomal pattern rarely have been reported. Bolognia et al¹ performed a comprehensive review of Blaschko lines and skin conditions that follow such a pattern. The authors found that adnexal-related lesions included linear nevus comedonicus, linear basal cell nevus with comedones (linear basaloid follicular hamartoma), unilateral nevoid basal cell carcinoma (BCC), linear trichoepithelioma, linear trichodiscoma, linear hamartoma of the follicular infundibulum, nevus sebaceous, syringocystadenoma papilliferum, porokeratotic eccrine ostial and dermal duct nevus, linear eccrine poroma, linear spiradenoma, linear syringoma, and linear eccrine syringofibroadenoma.¹  

Trichoepithelioma is a hair follicle-related neoplastic lesion presenting most commonly as the autosomal-dominant multiple familial type with lesions mainly centered on the face. Initial genetic studies associated the disease with loss of heterozygosity in the 9p21 region and further studies identified mutations in the CYLD (cylindromatosis [turban tumor syndrome]) gene on chromosome 16q12-q13.^2,3 Unilateral, linear, and dermatomal forms of trichoepithelioma rarely are reported. In 1986, Geffner et al⁴ reported a case of linear and dermatomal trichoepithelioma in a 10-year-old girl. In addition to discrete solitary lesions affecting the face, she developed lesions on the left shoulder, left side of the trunk, and left lower leg following dermatomal distribution. In 2006, 2 cases of dermatomal trichoepitheliomas affecting the face in children, as in our case, were reported.^5,6 Another case involving the neck was reported in 2016.⁷ Although classic multiple familial trichoepithelioma can be part of conditions such as Brooke-Spiegler⁸ and Rombo syndromes,⁹ no syndromal association has been reported thus far with the unilateral, linear, or dermatomal variants.  

Our case showed typical histopathologic features of trichoepithelioma, including discrete islands of basaloid cells in the dermis set in a conspicuous fibroblastic stroma. Focal connection with the epidermis was present. Most of the islands showed peripheral palisading and horn cysts lined by eosinophilic cells. The fibroblastic component was tightly adherent to the epithelial component, and only stromal clefts were detected. Papillary mesenchymal bodies also were detected as oval aggregates of fibroblastic cells invaginating into epithelial islands to form hair papillae. 

Histopathologically, the 2 most important differential diagnoses of trichoepithelioma include BCC and basaloid follicular hamartoma. In differentiating BCC from trichoepithelioma, the presence of dense fibroblastic stroma and papillary mesenchymal bodies characterize trichoepithelioma, while a fibromucinous stroma with mucinous retraction artifacts and clefting between the basaloid islands and the stroma characterize BCC (Figure 1).¹⁰ Immunohistochemical studies using antibodies against Bcl-2, CD34, CD10, androgen receptor, Ki-67, cytokeratin 19, and PHLDA1 (pleckstrin homologylike domain family A member 1) have reportedly been utilized to differentiate trichoepithelioma from BCC.^11,12 Basaloid follicular hamartoma is characterized by thin anastomosing strands and branching cords of undifferentiated basaloid cells that replace or associate hair follicles in a latticelike pattern (Figure 2). The strands usually are vertically oriented perpendicular to the epidermis. Peripheral palisading is possible, and the basaloid strands are surrounded with cellular connective tissue stroma.¹³ Tumor islands in eccrine poroma show broad connections with the epidermis and are composed of poroid cells that show evident ductal differentiation with eosinophilic cuticles (Figure 3).¹⁴ Spiradenoma is characterized by capsulated deep-seated tumorous nodules not connected with the epidermis and composed of light and dark cells with ductal differentiation and vascular stroma (Figure 4). Scattered lymphocytes within the tumor lobules and in the stroma also are seen. Eosinophilic hyaline globules rarely can be present.¹⁵ 

Many pathologists consider trichoepithelioma as the superficial variant of trichoblastoma. According to the recent World Health Organization classification of benign tumors with follicular differentiation, trichoepithelioma is considered synonymous with trichoblastoma.¹⁶ 

Trichoepitheliomas are benign tumors, and therapy is mainly directed at removal for cosmetic purposes. Several methods of removal are available including electrocautery, laser therapy, and surgery. Awareness of the possible dermatomal distribution of hair follicle and other adnexal-related conditions is important, and such lesions should be thought of in the differential diagnosis of unilateral and/or dermatomal lesions.

The Diagnosis: Unilateral Dermatomal Trichoepithelioma  

Adnexal lesions presenting with a linear and/or dermatomal pattern rarely have been reported. Bolognia et al¹ performed a comprehensive review of Blaschko lines and skin conditions that follow such a pattern. The authors found that adnexal-related lesions included linear nevus comedonicus, linear basal cell nevus with comedones (linear basaloid follicular hamartoma), unilateral nevoid basal cell carcinoma (BCC), linear trichoepithelioma, linear trichodiscoma, linear hamartoma of the follicular infundibulum, nevus sebaceous, syringocystadenoma papilliferum, porokeratotic eccrine ostial and dermal duct nevus, linear eccrine poroma, linear spiradenoma, linear syringoma, and linear eccrine syringofibroadenoma.¹  

Trichoepithelioma is a hair follicle-related neoplastic lesion presenting most commonly as the autosomal-dominant multiple familial type with lesions mainly centered on the face. Initial genetic studies associated the disease with loss of heterozygosity in the 9p21 region and further studies identified mutations in the CYLD (cylindromatosis [turban tumor syndrome]) gene on chromosome 16q12-q13.^2,3 Unilateral, linear, and dermatomal forms of trichoepithelioma rarely are reported. In 1986, Geffner et al⁴ reported a case of linear and dermatomal trichoepithelioma in a 10-year-old girl. In addition to discrete solitary lesions affecting the face, she developed lesions on the left shoulder, left side of the trunk, and left lower leg following dermatomal distribution. In 2006, 2 cases of dermatomal trichoepitheliomas affecting the face in children, as in our case, were reported.^5,6 Another case involving the neck was reported in 2016.⁷ Although classic multiple familial trichoepithelioma can be part of conditions such as Brooke-Spiegler⁸ and Rombo syndromes,⁹ no syndromal association has been reported thus far with the unilateral, linear, or dermatomal variants.  

Our case showed typical histopathologic features of trichoepithelioma, including discrete islands of basaloid cells in the dermis set in a conspicuous fibroblastic stroma. Focal connection with the epidermis was present. Most of the islands showed peripheral palisading and horn cysts lined by eosinophilic cells. The fibroblastic component was tightly adherent to the epithelial component, and only stromal clefts were detected. Papillary mesenchymal bodies also were detected as oval aggregates of fibroblastic cells invaginating into epithelial islands to form hair papillae. 

Histopathologically, the 2 most important differential diagnoses of trichoepithelioma include BCC and basaloid follicular hamartoma. In differentiating BCC from trichoepithelioma, the presence of dense fibroblastic stroma and papillary mesenchymal bodies characterize trichoepithelioma, while a fibromucinous stroma with mucinous retraction artifacts and clefting between the basaloid islands and the stroma characterize BCC (Figure 1).¹⁰ Immunohistochemical studies using antibodies against Bcl-2, CD34, CD10, androgen receptor, Ki-67, cytokeratin 19, and PHLDA1 (pleckstrin homologylike domain family A member 1) have reportedly been utilized to differentiate trichoepithelioma from BCC.^11,12 Basaloid follicular hamartoma is characterized by thin anastomosing strands and branching cords of undifferentiated basaloid cells that replace or associate hair follicles in a latticelike pattern (Figure 2). The strands usually are vertically oriented perpendicular to the epidermis. Peripheral palisading is possible, and the basaloid strands are surrounded with cellular connective tissue stroma.¹³ Tumor islands in eccrine poroma show broad connections with the epidermis and are composed of poroid cells that show evident ductal differentiation with eosinophilic cuticles (Figure 3).¹⁴ Spiradenoma is characterized by capsulated deep-seated tumorous nodules not connected with the epidermis and composed of light and dark cells with ductal differentiation and vascular stroma (Figure 4). Scattered lymphocytes within the tumor lobules and in the stroma also are seen. Eosinophilic hyaline globules rarely can be present.¹⁵ 

Many pathologists consider trichoepithelioma as the superficial variant of trichoblastoma. According to the recent World Health Organization classification of benign tumors with follicular differentiation, trichoepithelioma is considered synonymous with trichoblastoma.¹⁶ 

Trichoepitheliomas are benign tumors, and therapy is mainly directed at removal for cosmetic purposes. Several methods of removal are available including electrocautery, laser therapy, and surgery. Awareness of the possible dermatomal distribution of hair follicle and other adnexal-related conditions is important, and such lesions should be thought of in the differential diagnosis of unilateral and/or dermatomal lesions.