Brian S. Hoyt, MD

The Diagnosis: Kaposi Varicelliform Eruption (Eczema Herpeticum) 

Polymerase chain reaction confirmed presence of herpes simplex virus (HSV) type 1, and the patient was started on intravenous acyclovir (10 mg/kg every 8 hours). Diagnosis was further supported by histopathologic examination with confirmatory immunohistochemistry (Figure 1). The patient's anemia and thrombocytopenia also were attributed to widespread HSV infection. 

Approximately 8 hours after the patient was started on acyclovir, he developed increasing tremors, confusion, and impaired speech. Lumbar puncture confirmed the presence of HSV-1 in the cerebrospinal fluid. Despite ongoing intravenous antiviral therapy, he required intubation 6 days after hospitalization due to impaired mental status and myoclonic jerking. He remained intubated, unresponsive, and in critical condition for 9 days before he gradually began to demonstrate cognitive recovery. He subsequently was weaned off the ventilator, his mental status returned to normal, and his skin rash slowly resolved (Figure 2). 

Hailey-Hailey disease (HHD), also known as familial benign chronic pemphigus, is a rare autosomal-dominant condition first described by Howard and Hugh Hailey in 1939.¹ It is a chronic blistering process characterized by epidermal fragility, often manifesting as macerated fissured erosions in areas exposed to heat and friction (eg, axillae, groin). Hailey-Hailey disease results from a defective calcium transporter (ATP2C1 gene), leading to impaired keratinocyte adhesion.² 

Eczema herpeticum refers to the dissemination of herpes infection to areas of compromised skin barrier. Although originally used to describe HSV infection in patients with atopic dermatitis, eczema herpeticum has been described in various conditions that affect the skin barrier function, including Darier disease, ichthyosis vulgaris, pemphigus foliaceus, pemphigus vulgaris, and mycosis fungoides, among others.³ When applied to skin conditions other than atopic dermatitis, it sometimes is referred to as Kaposi varicelliform eruption.² 

Hailey-Hailey disease commonly is complicated by a bacterial or fungal infection, including impetigo, tinea, or candidiasis. The first case of HHD complicated by HSV infection was reported in 1973.⁴ A PubMed search of articles indexed for MEDLINE using the terms benign familial pemphigus AND herpes, Hailey-Hailey AND herpes, Hailey-Hailey AND eczema herpeticum, Hailey-Hailey AND Kaposi varicelliform eruption, and Hailey-Hailey herpeticum revealed 15 cases of HHD complicated by eczema herpeticum.^4-6 Herpes simplex virus encephalitis is a rare and life-threatening complication of eczema herpeticum.^7,8 We report a case of HSV encephalitis resulting from eczema herpeticum in a patient with HHD.  

The clinical differential includes a flare of the patient's known HHD, secondary bacterial or fungal infection, or a superimposed viral infection (eg, HSV, zoster). Histologic evidence of herpetic infection would be absent in an uncomplicated flare of HHD. Impetigo is a superficial bacterial infection that can present in 2 clinical forms: a vesiculopustular type and less commonly a bullous type. It is caused by Staphylococcus aureus in most cases. In multiple myeloma with cutaneous dissemination, a monoclonal proliferation of plasma cells would be evident. Lastly, tinea corporis is caused by dermatophytes that can be seen on hematoxylin and eosin or periodic acid-Schiff staining.  

The diagnosis of eczema herpeticum in a patient with HHD should be considered in patients who present with grouped vesicles or hemorrhagic or punched-out erosions in areas of pre-existing HHD. The diagnosis can be confirmed by Tzanck smear, viral culture, polymerase chain reaction, or histopathology (with or without immunohistochemistry).^1,2,6 When eczema herpeticum is suspected, prompt antiviral administration is imperative to limit life-threatening systemic spread. 

The Diagnosis: Kaposi Varicelliform Eruption (Eczema Herpeticum) 

Polymerase chain reaction confirmed presence of herpes simplex virus (HSV) type 1, and the patient was started on intravenous acyclovir (10 mg/kg every 8 hours). Diagnosis was further supported by histopathologic examination with confirmatory immunohistochemistry (Figure 1). The patient's anemia and thrombocytopenia also were attributed to widespread HSV infection. 

Approximately 8 hours after the patient was started on acyclovir, he developed increasing tremors, confusion, and impaired speech. Lumbar puncture confirmed the presence of HSV-1 in the cerebrospinal fluid. Despite ongoing intravenous antiviral therapy, he required intubation 6 days after hospitalization due to impaired mental status and myoclonic jerking. He remained intubated, unresponsive, and in critical condition for 9 days before he gradually began to demonstrate cognitive recovery. He subsequently was weaned off the ventilator, his mental status returned to normal, and his skin rash slowly resolved (Figure 2). 

Hailey-Hailey disease (HHD), also known as familial benign chronic pemphigus, is a rare autosomal-dominant condition first described by Howard and Hugh Hailey in 1939.¹ It is a chronic blistering process characterized by epidermal fragility, often manifesting as macerated fissured erosions in areas exposed to heat and friction (eg, axillae, groin). Hailey-Hailey disease results from a defective calcium transporter (ATP2C1 gene), leading to impaired keratinocyte adhesion.² 

Eczema herpeticum refers to the dissemination of herpes infection to areas of compromised skin barrier. Although originally used to describe HSV infection in patients with atopic dermatitis, eczema herpeticum has been described in various conditions that affect the skin barrier function, including Darier disease, ichthyosis vulgaris, pemphigus foliaceus, pemphigus vulgaris, and mycosis fungoides, among others.³ When applied to skin conditions other than atopic dermatitis, it sometimes is referred to as Kaposi varicelliform eruption.² 

Hailey-Hailey disease commonly is complicated by a bacterial or fungal infection, including impetigo, tinea, or candidiasis. The first case of HHD complicated by HSV infection was reported in 1973.⁴ A PubMed search of articles indexed for MEDLINE using the terms benign familial pemphigus AND herpes, Hailey-Hailey AND herpes, Hailey-Hailey AND eczema herpeticum, Hailey-Hailey AND Kaposi varicelliform eruption, and Hailey-Hailey herpeticum revealed 15 cases of HHD complicated by eczema herpeticum.^4-6 Herpes simplex virus encephalitis is a rare and life-threatening complication of eczema herpeticum.^7,8 We report a case of HSV encephalitis resulting from eczema herpeticum in a patient with HHD.  

The clinical differential includes a flare of the patient's known HHD, secondary bacterial or fungal infection, or a superimposed viral infection (eg, HSV, zoster). Histologic evidence of herpetic infection would be absent in an uncomplicated flare of HHD. Impetigo is a superficial bacterial infection that can present in 2 clinical forms: a vesiculopustular type and less commonly a bullous type. It is caused by Staphylococcus aureus in most cases. In multiple myeloma with cutaneous dissemination, a monoclonal proliferation of plasma cells would be evident. Lastly, tinea corporis is caused by dermatophytes that can be seen on hematoxylin and eosin or periodic acid-Schiff staining.  

The diagnosis of eczema herpeticum in a patient with HHD should be considered in patients who present with grouped vesicles or hemorrhagic or punched-out erosions in areas of pre-existing HHD. The diagnosis can be confirmed by Tzanck smear, viral culture, polymerase chain reaction, or histopathology (with or without immunohistochemistry).^1,2,6 When eczema herpeticum is suspected, prompt antiviral administration is imperative to limit life-threatening systemic spread. 

The Diagnosis: Kaposi Varicelliform Eruption (Eczema Herpeticum) 

Polymerase chain reaction confirmed presence of herpes simplex virus (HSV) type 1, and the patient was started on intravenous acyclovir (10 mg/kg every 8 hours). Diagnosis was further supported by histopathologic examination with confirmatory immunohistochemistry (Figure 1). The patient's anemia and thrombocytopenia also were attributed to widespread HSV infection. 

Approximately 8 hours after the patient was started on acyclovir, he developed increasing tremors, confusion, and impaired speech. Lumbar puncture confirmed the presence of HSV-1 in the cerebrospinal fluid. Despite ongoing intravenous antiviral therapy, he required intubation 6 days after hospitalization due to impaired mental status and myoclonic jerking. He remained intubated, unresponsive, and in critical condition for 9 days before he gradually began to demonstrate cognitive recovery. He subsequently was weaned off the ventilator, his mental status returned to normal, and his skin rash slowly resolved (Figure 2). 

Hailey-Hailey disease (HHD), also known as familial benign chronic pemphigus, is a rare autosomal-dominant condition first described by Howard and Hugh Hailey in 1939.¹ It is a chronic blistering process characterized by epidermal fragility, often manifesting as macerated fissured erosions in areas exposed to heat and friction (eg, axillae, groin). Hailey-Hailey disease results from a defective calcium transporter (ATP2C1 gene), leading to impaired keratinocyte adhesion.² 

Eczema herpeticum refers to the dissemination of herpes infection to areas of compromised skin barrier. Although originally used to describe HSV infection in patients with atopic dermatitis, eczema herpeticum has been described in various conditions that affect the skin barrier function, including Darier disease, ichthyosis vulgaris, pemphigus foliaceus, pemphigus vulgaris, and mycosis fungoides, among others.³ When applied to skin conditions other than atopic dermatitis, it sometimes is referred to as Kaposi varicelliform eruption.² 

Hailey-Hailey disease commonly is complicated by a bacterial or fungal infection, including impetigo, tinea, or candidiasis. The first case of HHD complicated by HSV infection was reported in 1973.⁴ A PubMed search of articles indexed for MEDLINE using the terms benign familial pemphigus AND herpes, Hailey-Hailey AND herpes, Hailey-Hailey AND eczema herpeticum, Hailey-Hailey AND Kaposi varicelliform eruption, and Hailey-Hailey herpeticum revealed 15 cases of HHD complicated by eczema herpeticum.^4-6 Herpes simplex virus encephalitis is a rare and life-threatening complication of eczema herpeticum.^7,8 We report a case of HSV encephalitis resulting from eczema herpeticum in a patient with HHD.  

The clinical differential includes a flare of the patient's known HHD, secondary bacterial or fungal infection, or a superimposed viral infection (eg, HSV, zoster). Histologic evidence of herpetic infection would be absent in an uncomplicated flare of HHD. Impetigo is a superficial bacterial infection that can present in 2 clinical forms: a vesiculopustular type and less commonly a bullous type. It is caused by Staphylococcus aureus in most cases. In multiple myeloma with cutaneous dissemination, a monoclonal proliferation of plasma cells would be evident. Lastly, tinea corporis is caused by dermatophytes that can be seen on hematoxylin and eosin or periodic acid-Schiff staining.  

The diagnosis of eczema herpeticum in a patient with HHD should be considered in patients who present with grouped vesicles or hemorrhagic or punched-out erosions in areas of pre-existing HHD. The diagnosis can be confirmed by Tzanck smear, viral culture, polymerase chain reaction, or histopathology (with or without immunohistochemistry).^1,2,6 When eczema herpeticum is suspected, prompt antiviral administration is imperative to limit life-threatening systemic spread. 

The Diagnosis: Aneurysmal Dermatofibroma

Biopsy of the lesion revealed a circumscribed dermal nodule comprised of storiform arrangements of enlarged, plump, fibrohistiocytic cells punctuated by variably sized clefts and large cystic spaces filled with blood that lacked an endothelial lining. No bizarre nuclear pleomorphism, atypical mitoses, or tumor necrosis were identified. The overlying epidermis exhibited mild acanthosis with broadening of the rete ridges. Proliferative spindled cells entrapped dermal collagen bundles at the periphery. Hemosiderin-laden macrophages were present throughout the proliferation and in the adjacent dermis (Figure). These findings supported the diagnosis of aneurysmal dermatofibroma (ADF).

Aneurysmal dermatofibroma, also known as aneurysmal fibrous histiocytoma, is a rare variant of dermatofibroma that was described by Santa Cruz et al¹ in 1981 and represents 2% to 6% of dermatofibromas.^1,2 Aneurysmal dermatofibromas often lack the characteristic clinical and dermoscopic findings of conventional dermatofibromas, creating a diagnostic challenge for the clinician.³ Incomplete excision of this benign tumor was associated with a local recurrence rate of 19% (5/26) in one study,⁴ in contrast with the exceedingly low rate of local recurrence (<2%) attributed to conventional dermatofibromas.^2,4

Clinically, ADFs commonly appear as blue-brown nodules on the arms and legs, often with a history of rapid and sometimes painful growth.¹ Clinically, an ADF can have vascular, cystic, or melanocytic features that, in the context of lacking typical clinical findings of a dermatofibroma, can complicate clinical diagnosis; for example, ADFs can demonstrate several melanomalike features including atypical vessels, chrysalis structures, blue-white structures, a pinkish-white veil, irregular brown globulelike structures, an atypical pigment network, color variegation, a multicomponent pattern, and ulceration.³ Alternatively, ADFs can present with a vascular tumor-like pattern consisting of white areas and globular blue-red areas or a polymorphous vascular pattern with a peripheral collarette.

Our case illustrates the classic histologic appearance of an ADF. Large cavities and slitlike spaces filled with blood distinguish this entity from conventional dermatofibroma and other dermatofibroma variants; for example, cellular dermatofibroma is a benign variant of dermatofibroma that exhibits crowded fascicular architecture without an increase in vascular spaces. Aneurysmal dermatofibromas also should be distinguished from angiomatoid fibrous histiocytoma, which has intermediate malignant potential despite a similar-sounding name and a similar nodular appearance with large blood-filled spaces; however, many cases are located predominantly in the subcutis with epithelioid morphology, desmin immunohistochemical reactivity, and prominent tumor-associated lymphoid proliferation that can be mistaken for a lymph node.⁵ Furthermore, in contrast with vascular tumors, the blood-filled spaces of ADFs do not have an endothelial lining.

In summary, ADF is a rare dermatofibroma variant that has a variety of clinical presentations, often masquerading as a cyst, vascular tumor, or melanocytic neoplasm. The classic histopathologic features confirm the diagnosis. Although ADFs can be painful and have a tendency to recur, these lesions have a benign clinical course.

The Diagnosis: Aneurysmal Dermatofibroma

Biopsy of the lesion revealed a circumscribed dermal nodule comprised of storiform arrangements of enlarged, plump, fibrohistiocytic cells punctuated by variably sized clefts and large cystic spaces filled with blood that lacked an endothelial lining. No bizarre nuclear pleomorphism, atypical mitoses, or tumor necrosis were identified. The overlying epidermis exhibited mild acanthosis with broadening of the rete ridges. Proliferative spindled cells entrapped dermal collagen bundles at the periphery. Hemosiderin-laden macrophages were present throughout the proliferation and in the adjacent dermis (Figure). These findings supported the diagnosis of aneurysmal dermatofibroma (ADF).

Aneurysmal dermatofibroma, also known as aneurysmal fibrous histiocytoma, is a rare variant of dermatofibroma that was described by Santa Cruz et al¹ in 1981 and represents 2% to 6% of dermatofibromas.^1,2 Aneurysmal dermatofibromas often lack the characteristic clinical and dermoscopic findings of conventional dermatofibromas, creating a diagnostic challenge for the clinician.³ Incomplete excision of this benign tumor was associated with a local recurrence rate of 19% (5/26) in one study,⁴ in contrast with the exceedingly low rate of local recurrence (<2%) attributed to conventional dermatofibromas.^2,4

Clinically, ADFs commonly appear as blue-brown nodules on the arms and legs, often with a history of rapid and sometimes painful growth.¹ Clinically, an ADF can have vascular, cystic, or melanocytic features that, in the context of lacking typical clinical findings of a dermatofibroma, can complicate clinical diagnosis; for example, ADFs can demonstrate several melanomalike features including atypical vessels, chrysalis structures, blue-white structures, a pinkish-white veil, irregular brown globulelike structures, an atypical pigment network, color variegation, a multicomponent pattern, and ulceration.³ Alternatively, ADFs can present with a vascular tumor-like pattern consisting of white areas and globular blue-red areas or a polymorphous vascular pattern with a peripheral collarette.

Our case illustrates the classic histologic appearance of an ADF. Large cavities and slitlike spaces filled with blood distinguish this entity from conventional dermatofibroma and other dermatofibroma variants; for example, cellular dermatofibroma is a benign variant of dermatofibroma that exhibits crowded fascicular architecture without an increase in vascular spaces. Aneurysmal dermatofibromas also should be distinguished from angiomatoid fibrous histiocytoma, which has intermediate malignant potential despite a similar-sounding name and a similar nodular appearance with large blood-filled spaces; however, many cases are located predominantly in the subcutis with epithelioid morphology, desmin immunohistochemical reactivity, and prominent tumor-associated lymphoid proliferation that can be mistaken for a lymph node.⁵ Furthermore, in contrast with vascular tumors, the blood-filled spaces of ADFs do not have an endothelial lining.

In summary, ADF is a rare dermatofibroma variant that has a variety of clinical presentations, often masquerading as a cyst, vascular tumor, or melanocytic neoplasm. The classic histopathologic features confirm the diagnosis. Although ADFs can be painful and have a tendency to recur, these lesions have a benign clinical course.

The Diagnosis: Aneurysmal Dermatofibroma

Biopsy of the lesion revealed a circumscribed dermal nodule comprised of storiform arrangements of enlarged, plump, fibrohistiocytic cells punctuated by variably sized clefts and large cystic spaces filled with blood that lacked an endothelial lining. No bizarre nuclear pleomorphism, atypical mitoses, or tumor necrosis were identified. The overlying epidermis exhibited mild acanthosis with broadening of the rete ridges. Proliferative spindled cells entrapped dermal collagen bundles at the periphery. Hemosiderin-laden macrophages were present throughout the proliferation and in the adjacent dermis (Figure). These findings supported the diagnosis of aneurysmal dermatofibroma (ADF).

Aneurysmal dermatofibroma, also known as aneurysmal fibrous histiocytoma, is a rare variant of dermatofibroma that was described by Santa Cruz et al¹ in 1981 and represents 2% to 6% of dermatofibromas.^1,2 Aneurysmal dermatofibromas often lack the characteristic clinical and dermoscopic findings of conventional dermatofibromas, creating a diagnostic challenge for the clinician.³ Incomplete excision of this benign tumor was associated with a local recurrence rate of 19% (5/26) in one study,⁴ in contrast with the exceedingly low rate of local recurrence (<2%) attributed to conventional dermatofibromas.^2,4

Clinically, ADFs commonly appear as blue-brown nodules on the arms and legs, often with a history of rapid and sometimes painful growth.¹ Clinically, an ADF can have vascular, cystic, or melanocytic features that, in the context of lacking typical clinical findings of a dermatofibroma, can complicate clinical diagnosis; for example, ADFs can demonstrate several melanomalike features including atypical vessels, chrysalis structures, blue-white structures, a pinkish-white veil, irregular brown globulelike structures, an atypical pigment network, color variegation, a multicomponent pattern, and ulceration.³ Alternatively, ADFs can present with a vascular tumor-like pattern consisting of white areas and globular blue-red areas or a polymorphous vascular pattern with a peripheral collarette.

Our case illustrates the classic histologic appearance of an ADF. Large cavities and slitlike spaces filled with blood distinguish this entity from conventional dermatofibroma and other dermatofibroma variants; for example, cellular dermatofibroma is a benign variant of dermatofibroma that exhibits crowded fascicular architecture without an increase in vascular spaces. Aneurysmal dermatofibromas also should be distinguished from angiomatoid fibrous histiocytoma, which has intermediate malignant potential despite a similar-sounding name and a similar nodular appearance with large blood-filled spaces; however, many cases are located predominantly in the subcutis with epithelioid morphology, desmin immunohistochemical reactivity, and prominent tumor-associated lymphoid proliferation that can be mistaken for a lymph node.⁵ Furthermore, in contrast with vascular tumors, the blood-filled spaces of ADFs do not have an endothelial lining.

In summary, ADF is a rare dermatofibroma variant that has a variety of clinical presentations, often masquerading as a cyst, vascular tumor, or melanocytic neoplasm. The classic histopathologic features confirm the diagnosis. Although ADFs can be painful and have a tendency to recur, these lesions have a benign clinical course.