ACRAL MELANOCYTIC NEOPLASMS - A HISTOLOGIC ANALYSIS OF 158 LESIONS

Background: Acral nevi occasionally demonstrate pagetoid spread of mel anocytes. This feature may be of considerable concern because it is co mmonly associated with melanoma. Other features of melanoma must be as sessed to accurately classify these neoplasms as benign. Objective: We examined acral melanocytic lesions, benign and malignant, to evaluate their features. Methods: A retrospective analysis during 3 years was performed on 158 acral pigmented lesions diagnosed by the dermatopatho logy service. Blue nevi, intradermal nevi, lentigines, and Spitz nevi were excluded. The specimens were divided into three groups: benign ne vi, benign nevi with pagetoid spread, and melanoma. They were evaluate d for circumscription, symmetry, papillary dermal fibroplasia, bridgin g between rete ridges, inflammatory infiltrate, pagetoid spread, cytol ogic atypia, and mitotic activity. Results: Most lesions (60%) were co mpound nevi and 84% were from the foot. Ten specimens were melanomas ( 6%) and 28 (18%) were nevi with architectural disorder. Pagetoid sprea d of melanocytes, often minimal, was found in 57 benign lesions. Howev er, these nevi did not demonstrate the degree of pagetoid spread, cell ular atypia, inflammation, and asymmetry found in malignant lesions. C onclusion: The presence of pagetoid spread of melanocytes is common in otherwise benign acral nevi. Other parameters of malignancy in these neoplasms must be evaluated to determine their biologic potential.