Acral melanoma in Japan.

Clinical records and histologic materials from 81 patients with malignant melanoma at the Department of Dermatology at Tohoku University School of Medicine were reviewed. In addition, a statistical study on 1597 cases of malignant melanoma collected from the Japanese literature from 1961 to 1982 was performed. The annual mortality rate has been increasing almost linearly over the past 20 years. The mortality rate per year for 1980 was 0.21 per 100,000. Five-year survival rate at Tohoku University was 35 percent. The most common site of melanoma was acral, especially the plantar surfaces. The clinical and histologic study of acral melanomas showed that clinicopathologic features are the same as those reported for acral lentiginous melanoma in the United States.