Oral malignant melanoma in Japan.

Clinical examination was performed on 20 cases of malignant melanoma in the oral region encountered at the First Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University, during the 22-year period from 1970 to 1991. In addition, we reviewed 140 cases reported in the Japanese literature since the last major review in 1974. The results of our study revealed that the clinical course of malignant melanoma in the oral region is worse than oral squamous cell carcinoma and that treatment by radiotherapy is effective in prolonging the life of these patients. Clinically, the tumors were classified into five types: (1) pigmented nodular type; (2) nonpigmented nodular type; (3) pigmented macular type; (4) pigmented mixed type; and (5) nonpigmented mixed type. We suggest that oral malignant melanoma might be different from cutaneous malignant melanoma and that new criteria for diagnosis and therapy for oral disease should be considered.