Oral cavity melanoma and its impact on delayed diagnosis

Abstract

Oral mucosal melanoma (OMM) is a rare and aggressive malignant neoplasm that accounts for between 0.2% and 8% of all melanomas and approximately 1.3% of oral cancers worldwide. Unlike cutaneous melanoma, its etiology is not yet fully understood, although it has been associated with factors such as chronic irritation, mechanical trauma, immunosuppression, and genetic predisposition. OMM is most frequently located on the hard palate and gingiva, typically presenting between the fourth and seventh decades of life, with no clear sex predilection. This tumor develops from melanocytes of the oral mucosa and exhibits highly invasive clinical behavior with a guarded prognosis. Clinical manifestations may include pigmented or amelanotic lesions that are asymptomatic in the early stages, which hinders early diagnosis. The differential diagnosis includes melanocytic nevi, oral melanosis, and pigmented squamous cell carcinoma. Definitive diagnosis is achieved through biopsy and immunohistochemistry, using markers such as S-100 protein, HMB-45, and Melan-A (Mart-1). The treatment of choice is surgical resection with wide margins, complemented by radiotherapy and systemic therapies such as immunotherapy in advanced cases. However, the five-year survival rate rarely exceeds 25% due to the high rate of recurrence and metastasis. Although no specific preventive measures exist, oral self-examination, regular clinical checkups, and education regarding warning signs are recommended. In conclusion, OMM represents a diagnostic and therapeutic challenge due to its low incidence and high lethality. Its silent presentation in early stages, together with the absence of specific clinical signs, complicates early diagnosis and results in low survival rates and an unfavorable prognosis.