Malignant melanomas of the vagina are rare; they constitute fewer than 1% of all melanomas occurring in females. The age distribution of the neoplasm has ranged from 26 to 98 years, with a median age of 70 years. Most patients are postmenopausal and present with vaginal bleeding, discharge, or a mass. Tumors may vary from 0.5 to 7.5 cm in diameter, with approximately 30% being 2 cm or less in diameter. Most of these tumors develop in the distal third of the vagina, commonly on the anterior wall.
Primary vaginal melanomas presumably arise from vaginal melanocytes that are present in approximately 3% of normal females. Histologically, this neoplasm is similar to other melanomas found elsewhere and tends to be deeply invasive in the vagina.
The prognosis is worse than that of vulvar melanomas. Chung and colleagues reported a 5-year survival rate of only 21% in a series of 19 patients. Reid and colleagues reported a 5-year survival rate of 17.4% in 15 cases, but the prognosis was improved for those tumors that were small and less than 3 cm in diameter. More recently, Borazjani and colleagues reported improved survival for cases in which there were fewer than six mitoses/10 high-power fields.
Optimal treatment has not been established. Treatment usually consists of radical surgery or wide excision of the vagina and dissection of the regional lymph nodes, depending on the location of the lesion. Because of the poor prognosis, adjunctive radiation and chemotherapy have been used as local recurrences, and distant metastases with this disease are common.
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