Amelanotic primary vaginal melanoma: A case report with cyto-histological correlations

Vaginal mucosa represents a rare site for primary melanoma. These neoplasms more commonly occur in the postmenopausal period, usually presenting with vaginal discharge, bleeding, or palpable mass. We report a case of an 89-year-old woman presenting with vaginal bleeding and a non-pigmented lesion in the lower third of the vagina at the gynaecological examination. A PAP smear and tissue incisional biopsy were concurrently performed. The cytological sample showed a subpopulation of non-cohesive, atypical epithelioid cells suggestive for malignancy. The histological examination showed the same morphological characteristics in the neoplastic population widely underlying the vaginal epithelium, with scattered intraepithelial nests and single elements. In both samples, there was no evidence of melanin pigment within the malignant cells. Immunohistochemical analysis performed on the tissue biopsy demonstrated a strong and diffuse positivity for melanocytic markers (HMB-45, S-100, Melan-A), confirming the diagnosis of primary amelanotic vaginal melanoma.