Amelanotic vulvar melanoma: case report and review of the literature.

A rare case of amelanotic vulvar melanoma is presented. The patient was a 71-year-old woman complaining of vulvar itching and yellowish vaginal discharge who underwent a complete gynecological evaluation during which a suspicious grey-whitish mass on her vulva was observed. The tumor presented superficial ulceration and was located in the upper half of the labia minora and clitoris. Initially it was suspected to be a vulvar carcinoma. A biopsy was taken and a histopathological suspicion of amelanotic melanoma was rendered. The mass was radically excised and the diagnosis was confirmed using HMB-45, Melan-A and anti-S-100 protein antibodies. Malignant melanoma is readily diagnosed by the presence of melanin granules. Although amelanotic melanoma contains a few melanin granules, it is often difficult to differentiate it from other non-epithelial malignant tumors. This report describes a case of amelanotic melanoma of the vulva, which was correctly diagnosed by immunohistochemical staining with the HMB-45, Melan-A antibody and for the S-100 protein.