Congenital Melanocytic Nevus Showing an Unusual Clinical Manifestation / 대한피부과학회지

ABSTRACT

Completely neurotized melanocytic nevi are often clinically and histologically indistinguishable from neurofibromas. We report a 23-year-old female who presented with a dark brown plaque with an underlying soft blue subcutaneous nodule in the left infra-axillary area. The skin biopsy revealed markedly increased melanocytic proliferation and nests of nevus cells within dermo-epidermal junction and upper dermis. Circumscribed, non-encapsulated tumor of the dermis was composed of loosely-spaced spindle cells and wavy stroma. Spindle cells in the lower dermis showed staining for S-100, but failed to express glial fibrillary acidic protein and Leu-7. We present an interesting case because the lesion presented as a soft blue subcutaneous nodule suggested an underlying hemangioma or neurofibroma initially, but was shown to be a neurotized melanocytic nevus based on immunohistochemical examination.