TABLE 1.

Histologic criteria for the diagnosis of malignant melanoma (after Ackerman) (Table 32.4, Weedon’s Skin Pathology[2].)

Architectural criteria

Asymmetry

Poor circumscription

Consumption of the epidermis

Epidermal nests of melanocytes showing: Confluence Variability in size and shape Haphazard interval and array

Solitary epidermal melanocytes showing: Predominance over nests Pagetoid spread Haphazard arrangement

Dermal nests showing: Variability in size and shape Confluence Lack of maturation in depth Variability in melanin distribution

Melanocytes within lymphovascular spaces

Cytological criteria

Nuclear pleomorphism

Nucleolar variability

Mitosis: Even deep Sometimes atypical

Apoptosis increased