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.