Acquired Melanocytic Nevus: An Unusual Case Presentation

Abstract

Acquired Melanocytic Nevi (AMV) are common benign pigmented skin lesions. There are three types which include junctional nevus, compound nevus and Intradermal Melanocytic Nevus (IMN). IMN are characterized clinically by dome-shaped, soft, fleshy papules and are seen commonly in adults. Herein we reported a case with an unusual large IMN. A 35 years old otherwise healthy male presented with history of asymptomatic skin lesion on his scalp of several years duration that started to get bigger within the previous few months prior presenting to us. Skin examination revealed solitary firm skin colored nodule measuring 1.5×1.5 cm on his scalp. Exccesional skin biopsy revealed sharply-defined intradermal tumor composed of nests and fascicles of nevus cells. The tumor cells in superficial dermis are composed of epithelioid cells arranged singly and in clusters with heavy pigmentation in the superficial part. The deeper portion of the tumor is composed of bland looking spindle cells. No atypia or mitosis has been seen. Nerve corpuscles resembling Meissner corpuscles have also been seen in the deeper portions of the tumor. Histochemical analysis showed positivity for S100 and HMB-45. On the basis of the above clinicopathological findings, the diagnosis of intradermal melanocytic nevus was made and the patient was reassured.