A case of atypical melanosis of the foot

Atypical melanosis of the foot showing a dermoscopic feature of the parallel ridge pattern

A 62-year-old male Turkish patient had a pigmented lesion on the sole with a 10-year history. It was an asymmetrical macular lesion with an irregular border and irregular brown pigmentation and had a diameter of 1.2 cm x 1.7 cm. Dermoscopy revealed a parallel ridge pattern and an abrupt cut-off of pigmentation on the upper edge. Histologically lentiginous hyperplasia decorated by innocent melanocytes and scattered melanocytic proliferation with slight to moderate cytological atypia were seen. Atypical melanocytes were very scattered and it was insufficient to call it a melanoma in situ. A second finding was a microvascular proliferation located in the papillary dermis. There was no sign of regression such as fibrous tissue or host reaction. Atypical melanosis of the foot has rarely been reported in the published work, which are from Japan and Korea. This case is presented to emphasize the significance of this rare entity which has recently been reported to be a very early phase of acral melanoma.