History
Angiokeratoma circumscriptum lesions are most commonly found on the lower extremities as an asymptomatic solitary papule or plaque, but they can also be found virtually anywhere, with dominance on the legs, upper extremities, and trunk. [14] One incidence of angiokeratoma circumscriptum involved an asymmetrical distribution in a systematized bandlike, segmental arrangement in the trunk, legs, and face. [15]
Several reports have noted angiokeratoma circumscriptum appearing on the ventral and, less commonly, the dorsal surface of the tongue. [16, 17, 18]
Occasionally, multiple lesions develop, usually after adolescence.
Patients may present with a rapid darkening or a change of the lesion.
Sometimes, patients may be specifically concerned about the possibility of melanoma, given the dark purple or black color of the lesion. [19] See the images below.
A hyperkeratotic, asymmetric, variably pigmented, black 3 X 4-mm papule was found on the upper right medial part of the arm of this 18-year-old woman, who was concerned about melanoma. The histologic analysis revealed a thrombosed angiokeratoma circumscriptum.
Physical Examination
The primary lesions of angiokeratoma consist of elevated, hyperkeratotic, dark red to purple or black, slightly compressible papules. Small nodules or plaques can also be seen. Sometimes, a linear distribution (with bands or streaks) of papules develops. A rough hyperkeratotic scale is often found over the surface and the edges of these papules due to epithelial hyperplasia and hyperkeratosis.
The lesions often have irregular borders and associated pigmentation, which is mostly attributable to intraepidermal hemorrhage or associated hemosiderin pigment deposition in the dermis. If excoriated or traumatized, angiokeratomas may present with epithelial erosion and bleeding.
When compressed with a glass slide, the dark purple or black color often blanches to red.
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A hyperkeratotic, asymmetric, variably pigmented, black 3 X 4-mm papule was found on the upper right medial part of the arm of this 18-year-old woman, who was concerned about melanoma. The histologic analysis revealed a thrombosed angiokeratoma circumscriptum.
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Close-up view of an asymmetric black angiokeratoma mimicking a melanoma.
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Low-magnification histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary dermis.
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This mid-power histologic view reveals dilated vessels in the papillary and upper reticular dermis. The vessels are packed with red blood cells; this finding is suggestive of vessel thrombosis.
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This high-power histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary dermis. Dilated vessels in the papillary and upper reticular dermis are observed. The vessels are packed with red blood cells; this finding is suggestive of vessel thrombosis. A normal-appearing vascular endothelium is found. No evidence of a melanocytic lesion is present.
