Malignant melanomas of the lower female genital tract

Abstract

Malignant melanomas (MM) that affect oral, ocular, respiratory and genital mucosa are rather rare neoplasms. Mucosal MMs usually escape early discovery due to their locations and are typically large, ulcerated, fungating advanced tumors at diagnosis. While cutaneous MM are slowly progressing indolent tumors when discovered early with metastases primarily to lymph nodes and only late hematogenous distant metastases, mucosal MMs of various locations have a poor prognosis with aggressive local growth, early hematogenous dissemination and rapid death. The vulva is a unique organ characterized by the transition from hair bearing skin to glycogenated mucosa, therefore vulvar MMs constitute a heterogeneous group of neoplasms. Dependent on the site of origin, vulvar MMs have to be divided into three major groups: cutaneous MM, mucosal MM and overlap MMs featuring both components, as therapy, prognosis and survival are dependent on the subtype. Cutaneous MMs are classified according to Clark levels (anatomical levels of skin containing adnexal structures) and the absolute depth of invasion (Breslow index) with the superficial spreading form as the most common subtype. Mucosal MMs are typically undifferentiated highly vascular amelanotic solid tumors. Cutaneous MMs react strongly with antibodies to S–100 and are usually negative with antibodies to HMB45. In contrast, mucosal MMs are strongly and uniformly positive for HMB45, while S–100 is inconsistently positive. Patients with cutaneous vulvar MM will benefit from a wide local excision and lymph node dissection, while mucosal MM with multifocal presentation and early distant metastases need systemic therapy. Overlap MM usually behave as mucosal MM.