Spontaneous Acroangiodermatitis.

Acroangiodermatitis is a rare self-limited angioproliferative lesion which can be associated with congenital vascular malformations or acquired venous insufficiency. Despite of its benign character, differential diagnosis of this lesion is very important because it closely resembles Kaposi sarcoma. Here we present a 26-year-old male patient with unilateral, purplish-red colored papules on his right ankle which diagnosed as acroangiodermatitis and discuss histopathological features, differential diagnosis and treatment of this unusual condition.

What was known?

Acroangiodermatitis has different names like congenital dysplastic angiopathy, pseudo-Kaposi sarcoma, and acral capillary angiomatosis.

Acroangiodermatitis is an angioproliferative disease and believed to be related to venous insufficiency.

Introduction

Acroangiodermatitis is a reactive angiodysplasia of cutaneous blood vessels.[1] It has been described in patients with increased venous pressure and stasis caused by venous insufficiency, congenital/acquired arteriovenous anomalies, arteriovenous shunts and lower limb paralysis or amputation stumps.[234] Different names, like congenital dysplastic angiopathy, pseudo-Kaposi sarcoma, and acral capillary angiomatosis,[5] have been used. Mali et al. coined the term “Acroangiodermatitis” that is favored in the recent literature.[56] There are two variants of acroangiodermatitis. First type namely the Mali type of acroangiodermatitis is related to chronic venous insuffiency and second the Stewart-Bluefarb type is associated with arteriovenous malformations.[5789] This lesion is usually encountered mostly on extensor surfaces of lower extremities, and clinically characterized by angiomatous red-violaceous, brown papules, plaques or nodules.[8] It is seen more frequently in males and according to underlying causes may be presented in childhood or early adulthood.[25]

Case Report

A 26-year-old male was admitted to our hospital with unilateral, multifocal irregularly contoured, purplish red colored, papular, plaque-shaped and nodular lesions on his right ankle. Clinical history was not remarkable. An incisional biopsy was performed. The biopsy material measured 2 × 0.8 × 0.2 cm in size.

Microscopically epidermis showed minimal achantosis with a melanin pigment increase in the basal cell layer. The lesion was located in dermis demonstrating a lobular architecture and was composed of small proliferating capillaries that are separating from each other with a slightly edematous matrix or forming nodular structures in which the luminal formations can hardly be identified. The endothelial cells, lining these structures, showed minimal atypia and mitosis. Stroma contained minimal spindle cell proliferation around vessels, diffuse hemosiderin granules and extravasated erythrocytes. There was also minimal lymphocytic infiltration around vessels [Figures 1-4].

Figure 1

Vascular lesion in dermis, lobuler architecture. (H and E, ×40)

Figure 4

Minimal atypia in endothelial cells. Hemosiderin pigment deposition. (H and E, ×400)

Lobuler architecture. Hemosiderin pigment deposition. (H and E, ×100)

No atypia in endothelial cells. (H and E, ×200)

For differential diagnosis, immunohistochemical stains CD 34, CD 31 and Factor 8 were used. Positive immunostainings for CD 34, CD 31, and Factor 8 were observed in endothelial cells Figure 5.

Figure 5

CD 34 positivity in endothelial cells. (CD 34, ×200)

Discussion

Acroangiodermatitis is vasoproliferative disorder which is mostly related to vascular stasis and venous insufficiency, but rare cases without venous dysfunction are reported as in our case.[110] Whereas some authors classify acroangiodermatitis as a vascular lesion,[2] it is a variant of stasis dermatitis and takes place in the group of eczematous diseases according to some authors.[11] Compared with other eczematous diseases it is more pigmented, and prone to develop stasis ulcers. Histologically stasis dermatitis includes more dilated papillary dermal small blood vessels and more hemosiderin accumulation, shows more fibrosis or even sclerosing panniculitis in older lesions.[11] Similar findings can be observed in acroangiodermatitis. In addition to these features, exuberant vascular proliferation is characteristic feature of acroangiodermatitis, which most importantly makes it resembling Kaposi sarcoma both histologically and clinically.[211]

Acroangiodermatitis has been commonly described in patients with increased venous pressure and stasis caused by mostly venous insufficiency,[2] less commonly congenital/acquired arteriovenous anomalies,[2] arteriovenous shunts and lower limb paralysis,[2] particularly at lower distal extremities.[21213] Although exact etiology is not clear, increased venous pressure and stasis cause chronic hypoxia which induces neovascularization and fibroblast proliferation.[113] The role of angiogenetic factors, like PGE1 and heparin, induced by several causes seems to be important in vascular proliferation.[14]

Histologically there is an expansion of the whole capillary bed throughout the dermis. There are thick-walled, dilated capillaries showing reduplication may be indicating angiomatous appearance. The endothelial cells lining these vessels are plump and CD 34 positive.[2] Some lesions may show nodular collections of vessels with narrow lumina. There may be mild perivascular fibroblastic proliferation. In addition to that, extravasated erythrocytes, horizontally arranged spindle cells, fibrosis, numerous hemosiderin pigment accumulation may be present.

Its differential diagnosis with Kaposi sarcoma is important. They resemble each other both clinically and histopathologically. Histopathological findings are similar especially when Kaposi sarcoma is in early stage. Similar appearance, hypertrophic and tortuous venules can be observed in deep dermis[13] but in Kaposi sarcoma the vessels have more jagged outline and may show “promontory sign” which is characterized by protruding new formed small vessels into the larger vascular space. In acroangiodermatitis the angiomatous capillaries are separated by an edematous matrix. They don’t lie “back to back” as in Kaposi sarcoma. An important feature is that in acroangiodermatitis there is proliferation of the preexisting vasculature rather than new vascular formation seen in Kaposi sarcoma.[13] In Kaposi sarcoma there is slit-like inconspicuous lumina, there are fascicles of spindle cells which are sometimes branching whereas in acroangiodermatitis vessels form nodular collections with narrow but more regular lumina. There may be mild perivascular fibroblastic proliferation around vessels in both lesions but these cells do not stain with CD 34 in acroangiodermatitis whereas they are positive with CD 34 in Kaposi sarcoma.[15] In Kaposi sarcoma there is atypia in endothelial cells, small hyaline globules due to erytrophagocytosis and plasma cells can be observed in perivascular inflammatory infiltrate but in acroangiodermatitis there is no or minimal atypia in endothelial cells and other findings are not usual.[1617] Characteristic features of Kaposi sarcoma and acroangiodermatitis are summarized in Table 1. There are other diseases like pigmented purpuric diseases, vasculitis, stasis dermatitis, vascular forms of fibrous histiyocytoma, and other hemangiomata in differential diagnosis of acroangiodermatitis. In stasis dermatitis there is more parakeratosis and spongiosis in epidermis, lesions are located deeper in dermis and there is more hemosiderin pigment deposition. In vasculitic lesions there is fibrinoid necrosis, and vascular proliferation is absent.[16] Doppler sonography may help to show underlying arteriovenous malformation or chronic venous insufficiency.[18]

Table 1

Kaposi sarcoma versus acroangiodermatitis

Treatment of acroangiodermatitis is important to prevent further complications such as bone demineralization, soft tissue destruction, congestive heart failure and infection.[1920] Treatment includes correction of any underlying congenital or acquired vascular disorder, conservative methods to reduce venous stasis, and local wound care.[17172021] Medical treatment has a limited value.[122]

With all these clinical, histopathological, and immunohistochemical findings we diagnosed this lesion as acroangiodermatitis. Here, it is discussed since no venous insufficiency or any reason for venous pressure increase and prominent stasis could be found. In addition, this lesion closely resembles Kaposi sarcoma and differential diagnosis is important as the treatment of Kaposi sarcoma involves skin grafting and radiotherapy.

What is new?

Acroangiodermatitis needs to be evaluated carefully and distinguished from Kaposi sarcoma.

Acroangiodermatitis can be seen without venous insufficiency or prominent venous stasis as in our case.