Malignant melanoma of the mucosa

Malignant melanoma of the mucosa, also known as mucosal melanoma, is a rare and aggressive form of melanoma that arises from melanocytes located in the mucosal membranes lining various body cavities. Unlike cutaneous melanoma, which develops on sun-exposed skin, mucosal melanoma occurs in areas such as the nasal cavity, paranasal sinuses, oral cavity, pharynx, vulva, vagina, anorectal region, and urinary tract. It accounts for approximately 1–2% of all melanoma cases and is not associated with ultraviolet radiation exposure. The etiology remains largely unknown, and no consistent hereditary pattern has been established. Mucosal melanoma typically presents at an advanced stage because early lesions in internal mucosal surfaces are often asymptomatic or produce nonspecific symptoms. Key clinical features depend on the site of origin and may include nasal obstruction, epistaxis (nosebleeds), oral pigmented lesions, vaginal bleeding, rectal bleeding, or a palpable mass. The disease tends to be more aggressive than cutaneous melanoma, with a higher rate of local recurrence and distant metastasis. It most commonly affects older adults, with a median age of diagnosis in the sixth to seventh decade of life. Treatment of mucosal melanoma is challenging and typically involves surgical resection with wide margins when feasible, which remains the primary therapeutic approach. Radiation therapy may be used as an adjunct, particularly when complete surgical excision is difficult due to anatomical constraints. Systemic therapies including immune checkpoint inhibitors (such as anti-PD-1 and anti-CTLA-4 agents) and targeted therapies (for tumors harboring KIT mutations, which are more common in mucosal melanoma than in cutaneous melanoma) have shown some benefit, though overall response rates tend to be lower than in cutaneous melanoma. The prognosis is generally poor, with five-year survival rates significantly lower than those for cutaneous melanoma, largely due to late-stage diagnosis and the biologically aggressive nature of the disease.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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