Acral angioosteoma cutis.

Acral angioosteoma cutis is a rare disease first described in 2006 that is characterized by vascular proliferation with ossification at the acral area, and which bears clinical similarity to pyogenic granuloma. However, there is no lobular pattern in the capillary proliferation that is a typical histopathological feature in pyogenic granuloma. Metaplastic cutaneous ossification is associated with multiple skin diseases and inflammatory conditions such as scars, nevi, basal cell carcinomas, pilomatricomas, chondroid syringomas, and venous stasis. It is rarely associated with vascular proliferation diseases like hemangiomas and pyogenic granulomas. We report a case of capillary proliferation with ectopic bone formation in a 43-year-old female who presented with an ulcerative, dome-shaped subungual nodule on the left fourth toe, which appeared to be a pyogenic granuloma. Because the biopsy findings showed no lobular capillary proliferation, we determined that this case was consistent with acral angioosteoma cutis.