Track: Case Reports

Topic: Other

Abstract:

Angiokeratomas are benign vascular tumors that typically present as a hyperkeratotic red-brown to black papule on the lower extremities. Characteristic histopathology includes superficial dermal vascular ectasia with overlying epidermal hyperplasia. A subungual angiokeratoma is extremely rare, with only a few cases ever reported. Clinical features described include longitudinal pigmentation and nail plate dystrophy with histopathologic features seen involving proximal nail bed and matrix. Causes of subungual pigmentation are diverse and comprise nail apparatus tumors, fungal infection, and melanocytic lesions. Given the propensity to cause pigmentation coupled with the rare location for this lesion to arise, subungual angiokeratomas are often not clinically suspected. We report on three cases of subungual angiokeratoma with novel clinical presentations that prompted biopsy for concern of a melanocytic process. Our three patients, from as young as 25-years-old, each presented with irregular blue to darkly pigmented, tender, and occasionally bleeding lesions noted on the distal fingertip with subungual extension without overlying nail dystrophy. Nail bed biopsies were performed following partial nail plate avulsion. Histopathology demonstrated numerous dilated vascular spaces in the dermal papillae and upper reticular dermis associated with overlying epidermal acanthosis, consistent with an angiokeratoma. Our cases were unique given the distal location and younger age. We will review these novel clinical features, illustrate the benefit of nail avulsion for optimal biopsy visualization and therapeutic removal, and discuss the causes of subungual pigmentation to highlight the significance of maintaining a broad clinical differential when faced with a pigmented lesion of the nail.

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Nathaniel Jellinek, MD