[Pathological and immunohistochemical studies on primary nasal mucosal malignant melanoma].

The pathological and immunohistochemical features of primary nasal mucosal malignant melanoma (PNMMM) were reported in 40 cases. The results showed that approximate 70% of PNMMM was polypoid. The principal features were the mixed existance of different cellular patterns and morphologies. Immunohistochemically, PNMMM reactivity to S-100 protein and vimentin was 90% and 77.5%, respectively, along with no reactivity to Keratin. We believe that PNMMM may arise from preexistant melocytes in nasal mucosa. Histological pleomorphism and immunohistochemical reactivity to S-100 protein and vimentin were of importance for diagnosis of PNMMM, especially for the amelanotic type.