Oral Melanoma: A South American Collaborative Series of 21 Cases

BACKGROUND: Oral melanoma is a rare and aggressive malignant neoplasm that typically exhibits variable degrees of pigmentation. Amelanotic variants further complicate clinical diagnosis by mimicking non-neoplastic lesions. The present study aimed to describe the clinicopathological characteristics, management, and outcomes of oral melanoma in South America. METHODS: This collaborative retrospective study included cases diagnosed between 2003 and 2025 from five oral pathology and oral medicine centers in Argentina, Venezuela, Colombia, and Brazil. Clinicopathological, treatment, and follow-up data were analyzed descriptively. RESULTS: Twenty-one cases of primary oral melanoma were analyzed. The mean age was 63.0 years, with a slight female predominance (52.4%). Most lesions were asymptomatic at diagnosis (78.3%) and involved the palate/maxillary gingiva (66.7%). Clinically, tumors (37.9%) and macules (27.6%) were the most frequent presentations. Histologically, melanotic melanoma predominated (76.2%). Melan-A, HMB-45, SOX10, and S-100 protein were the most frequently used immunohistochemical markers. Surgical resection was performed in 85.7% of cases. During follow-up, 52.6% of patients died. CONCLUSION: Data corroborate the clinicopathological profile of oral melanoma and expand current knowledge by documenting novel South American cases, underscoring its marked clinical heterogeneity, poor prognosis, and the critical importance of early recognition.