Ki67 Antigen as a Predictive Factor for Prognosis of Sinonasal Mucosal Melanoma

OBJECTIVES Sinonasal mucosal melanoma is a rare and aggressive disease. The aim of this study was to analyze the clinical features of patients with sinonasal mucosal melanoma and to determine the role of Ki67 antigen as a predictor of prognosis in sinonasal mucosal melanoma. METHODS This was a retrospective case-series study at a single institution, an academic tertiary referral center. From 1995 to 2007, 27 patients with sinonasal mucosal melanoma were reviewed retrospectively, and the expression of Ki67 antigen was assessed by immunohistochemistry. RESULTS The overall 5-yr survival rate was 33.9%. No significant differences were observed in 5-yr survival according to age, sex, stage, or the presence of melanin. The rates of local failure, regional failure, and distant failure were 37.0%, 14.8%, and 11.1%, respectively. Patients with spindle or mixed cell types had better prognoses than those with other cell types. At a cut-off value of 35%, patients with lower Ki67 scores showed better survival than those with higher Ki67 scores. CONCLUSION The presence of spindle or mixed cell types may indicate a better prognosis than other cell types. Ki67 immunostaining may be a useful predictor of prognosis in patients with mucosal malignant melanoma of the sinonasal tract.