Prognostic features of vulvar melanoma: a clinicopathologic analysis.

We studied 19 cases of vulvar melanoma to determine significant clinical and histologic prognostic predictors. The average follow-up time was 32 months. Fourteen patients died of melanoma, four patients are alive with no evidence of melanoma, and one patient is alive with residual melanoma. All disease-free survivors had clinical stage I disease and a maximum tumor thickness of 1.3 mm. The average mitotic count in this group was 5.5 per 10 high power fields (HPF) and 50% of the tumors were superficial spreading melanomas. All survivors were treated by radical vulvectomy with bilateral inguinal lymph node dissection. Of the nonsurvivors, four (28.5%) were clinical stage I, five (36%) were clinical stage II, four (28.5%) were clinical stage III, and one (7%) was clinical stage IV. The average tumor thickness for nonsurvivors was 9.5 mm (range 2.6-18 mm) and the average mitotic count was 13.3/10 HPF. Only three (21%) tumors from nonsurvivors were superficial spreading melanomas; the majority were nodular melanomas. The statistically significant prognostic predictors were clinical stage of disease and tumor thickness. Tumor type (i.e., superficial spreading, nodular, or acral lentiginous) correlated with tumor thickness and was indirectly related to prognosis. The mitotic count was also a useful prognostic feature.