Cutaneous melanocytic lesions: selected problem areas.

Cutaneous melanocytic proliferations are diverse morphologically, and their behavioral attributes may be difficult to discern with certainty. As a consequence, diagnostic anatomic pathologists regularly encounter problems in the interpretation of such lesions. This review considers several selected issues in that subject area, including proliferative congenital nevi, architecturally disordered (dysplastic) nevi, morphologic variants of Spitz nevus, atypical lentiginous melanocytic proliferations, nevoid melanoma, diagnostically deceptive histologic variants of melanoma, "epidermotropic" metastases of melanoma, and the relationship of melanoma microstages to tumor growth phases.