Primary malignant melanoma of the nasal cavity: a clinicopathologic study of nine cases.

Nine cases of primary malignant melanoma of the nasal cavity are presented. All the patients had epistaxis and nasal obstruction at admission. Gross aspect of the neoplasia showed a fungating mass located in the right nasal cavity in six cases and in the left nasal cavity in three. Eight tumors were formed by polygonal cells and one tumor by spindle cells. Melanosis of the adjacent mucosa was found in only 1 case. S-100 protein was demonstrated by indirect immunoperoxidase in all cases. The mean survival rate was 23.8 months. Prognosis was not related to the histologic pattern, cell atypia, necrosis, pigment secretion, or mitotic index. Radiotherapy seemed to have some beneficial influence on the survival but did not influence the local recurrence and metastatic spread of the disease.