Nevomelanocytic nevus with leukotrichia

Introduction

Nevomelanocytic nevus or the common mole is a collection of nevomelanocytes. These clusters of nevomelanocytes can be in the epidermis, dermis or both areas when they are categorized as junctional, dermal or compound nevus respectively. It is still a matter of debate whether the dermal melanocytes originate and drop from epidermis or are derived from Schwanr cells of nerves.[1],[2] Whatever may be their origin, the more important fact is that nevomelanocytes can be differentiated easily from melanocytes by light microscopy due to their clustered arrangement, absence of dendritic processes and a decreased tyrosinase activity. The melanocytic nevi vary in shape, size and exhibit age related variations.[3] We report an interesting development of leukotrichia over a darkly pigmented mole.

Case Report

A 32- year-old male presented with -development of grey hairs over a common mole present on his right arm since childhood. Examination revealed a 2.5 cm x 1.5 cm size, elevated pigmented mole with both gray and black hairs on the lateral aspect of right upper arm. The hairs were coarse, long and terminal. On cutaneous examination, sparse graying of scalp and other body hairs was also observed. A few other moles present over his trunk were devoid of hair. Patient was reassured about benign nature of development of these gray hairs due to normal aging process.

Discussion

Atypical nevomelanocytic nevus[3] may be round or oval in shape, papillomatous, dome - shaped, pedunculated or flat-topped. Usually pigmented, the melanocytic nevus may be skin colored when located intradermally. Surface of the nevi may reveal hairs that may be less than, equal to or greater than surrounding skin. Usually these are coarse, longer and darker than surrounding hair. A hairy pigmented nevus has often been termed as Becker′s nevus.

Typically a nevs appears after the first 6 to 12 months of life, grow as the body grows and regresses in later life. This age related change is reflected in the study on prevalence of nevi at various age intervals, being maximum in first three decades and minimum in the later half of life.[4] These changes have been more or less similar in both the sexes. These nevi exhibit morphological, topographical and numerological changes in relation to age, race and geographical distribution. Although, apparently a normal aging change, the graying of hair over a melanocytic nevus appears quite paradoxical and the same, to the best of our knowledge has not been reported earlier.