De novo intraepidermal epithelioid melanocytic dysplasia as a marker of the atypical mole phenotype – a clinical and pathological study of 75 patients

Abstract

We encountered a distinctive pattern of dysplastic intraepidermal melanocytic proliferation, which defies classification as a dysplastic melanocytic nevus, but in which the morphologic features fall short of a diagnosis of melanoma in situ. We designate such lesions as de novo intraepidermal epithelioid melanocytic dysplasia. From 75 patients, 82 skin biopsies were encountered that showed this distinctive morphology. Hematoxylin- and eosin-stained histologic sections were studied and the features were correlated with personal and family histories of dysplastic nevi and melanoma. The diagnosis of de novo melanocytic dysplasia was made in 27 male patients and 48 female patients (mean age: 44 years). The histologic hallmark was a pagetoid (single-cell) array of moderately to severely atypical epithelioid melanocytes within the epidermis. Seventy-three lesions were located on sun-exposed skin and nine on sun-protected skin. In 41 patients, there was an atypical mole phenotype, whereas 20 patients had a prior or subsequent diagnosis of melanoma with five of 16 patients questioned revealing a family history of melanoma. De novo intraepidermal epithelioid melanocytic dysplasia is a distinct entity associated with an atypical mole phenotype and a personal and/or family history of melanoma.