Histologic findings and prognosis of uveal malignant melanoma in Japanese patients

PURPOSE: To determine factors of uveal malignant melanoma that would help to predict prognosis in Japanese patients. METHODS: From 1969 to 1994, 23 eyes with uveal malignant melanoma were enucleated from 23 Japanese patients, and 16 of these patients were studied. In the 16 patients, enucleated eyes were evaluated for tumor characteristics, including cell type and microvascular architecture. Patient records were reviewed for follow-up therapy and outcome. Mortality rate was evaluated four years after enucleation. RESULTS: In Japanese patients with uveal malignant melanoma, the average tumor size was larger (average largest diameter, 11.36 mm; average in crease, 6.25 mm) and the average patient age was younger (55.2 years old) than previously reported for white populations. Patients with spindle cell type melanoma tended to have a better prognosis than those with epithelioid cell type (four-year mortality rates: spindle cell type, 0%; mixed cell type, 43%; epithelioid cell type, 66%). Microvascular architecture patterns interpreted as either network or closed loop patterns were associated with a poorer prognosis (network pattern, P = .03; closed loop pattern, P = .005). CONCLUSIONS: The prognosis for Japanese patients with uveal malignant melanoma is poorer, and epithelioid cell-type melanoma is more com mon, than has been reported in white populations, Mitotic figures are well correlated with poor prognosis, as are two microvascular patterns, the network pattern and the dosed loop pattern.