Vulvar malignant melanoma is relatively uncommon, accounting for 2–4% of primary malignant tumors of the vulva, making it the second most common type of primary vulvar malignancy. It is highly aggressive and has a poor prognosis. The condition is most frequently observed in women aged 65–75, with common symptoms including vulvar itching, bleeding, and an enlarging area of pigmentation. Based on the Hart line in the vaginal vestibule, vulvar malignant melanoma can be categorized into a skin type and a mucosal type. The Hart line is a thin line at the junction between the skin and the mucosal epithelium along the inner surface of the labia minora, extending to the navicular fossa. It separates the cutaneous tissues of the frenulum of the labia from the mucosal tissues of the hymen and serves as the boundary between the inner surface of the labia minora and the vestibule.
Figure 1 Schematic diagram of the Hart line
Skin-type lesions are most commonly located on the labia minora, followed by the area around the clitoris. They typically present as mole-like or nodular lesions with pigmentation (tumors usually appear brownish or bluish-black) and may be accompanied by ulceration. Diagnosis is based on histopathological evaluation of biopsy samples. Staging is conducted using the American Joint Committee on Cancer (AJCC) TNM staging system for cutaneous malignant melanoma.
The primary treatment is surgery, with surgical margins determined by the thickness of the tumor. Sentinel lymph node biopsy is the preferred initial approach, while inguino-femoral lymph node dissection is recommended only for patients with positive sentinel lymph nodes. Immunotherapeutic and targeted therapies represent the main options for systemic treatment of melanoma. First-line therapy typically consists of a combination of dual immune checkpoint inhibitors. For patients with BRAF V600 mutations, the combination of dabrafenib and trametinib, among other options, may be used. Chemotherapy is reserved for patients who are not candidates for immunotherapy or targeted therapy. Radiotherapy is only considered for patients who are unsuitable for surgery or chemotherapy.
The treatment of mucosal melanoma can be guided by approaches used for vaginal melanoma.