Malignant melanoma of the skin is an erratic tumor of rather unpredictable behavior. The prognosis is influenced by the presence or absence of metastases. In recent years studies by Clark et al. (1969) and Breslow (1975) have revealed several additional clinical and histologic characteristics of the primary tumor to which prognostic significance can be ascribed. Tumor size, depth of invasion, ulceration, vascular invasion, and lymphoid reaction along the under side of the tumor have been reported to be of importance in this respect. Olsen (1966), Bodenham (1968), Davis (1976), Milton (1977), and Shaw et al. (1978) reported that the location of the primary tumor and the patient’s sex are also factors influencing survival.