Track: Case Reports

Abstract:

Hormonal influences on melanocytic proliferations, including nevi and melanoma, are well documented in pregnancy and exogenous hormone therapy. However, reports describing such changes in the setting of gender-affirming hormone therapy are limited. We present a case of hormonally influenced melanocytic nevus in a transgender male on long-term exogenous hormone treatment. A 28-year-old transgender male presented with a slowly enlarging, pruritic and mildly tender scalp lesion, initially noted over a decade earlier and clinically considered a cutaneous acrochordon. The patient had been receiving medroxyprogesterone and testosterone cypionate since 2017. On examination, a 5 mm skin-colored papule was identified on the right superior occipital scalp. Biopsy revealed a lentiginous compound nevus with moderate atypia of the intraepidermal component without upward spread, confirmed by Melan-A immunostaining. The dermal component exhibited features favoring hormonal influence, including two melanocytic populations: (1) a predominant component of variably sized nevomelanocytes with maturation and (2) superficial dermal nests of smaller, monomorphic melanocytes positive for HMB-45 with a mildly increased Ki-67 proliferative index. PRAME was negative and BAP-1 expression was retained. These superficial nests resembled the “superficial micronodules” in pregnancy nevi previously described by Chan et al. This case illustrates alterations in a melanocytic nevus likely related to gender-affirming chronic hormone therapy and emphasizes the importance of clinicopathologic correlation when interpreting atypical changes in melanocytic lesions.