Pagetoid Spitz nevus. Intraepidermal Spitz tumor with prominent pagetoid spread.

A distinctive variant of melanocytic growth pattern is described, which appears to be related to Spitz nevus and is characterized by a mainly intraepidermal proliferation of large epithelioid melanocytes with a predominantly pagetoid distribution. This melanocytic lesion appears clinically as a small (< 0.4 cm) pigmented macule in young patients. Histologically, this lesion needs to be distinguished primarily from in situ or microinvasive malignant melanoma with pagetoid spread. Features favoring nevus over melanoma include small size, circumscription, symmetry, even distribution of cells, and lack of marked cytologic atypia.