Hypomelanotic melanoma of the mandibular gingiva: a case report and literature review

BACKGROUND: Oral mucosal melanoma (OMM) is a rare and aggressive malignancy that exhibits distinct clinical and pathological characteristics compared to cutaneous melanomas. The hypomelanotic subtype of OMM is even rarer, with clinical signs and symptoms often being nonspecific, complicating the diagnostic process and contributing to a poor prognosis. Due to its rarity and the frequent delays in diagnosis, case reports are an invaluable source of information regarding this condition. A 78-year-old male presented with a painless mass on the left mandibular gingiva, which was initially misidentified as an inflammatory gingival lesion. After ineffective anti-inflammatory treatment, further investigation led to a confirmed diagnosis of hypomelanotic melanoma through histopathological and immunohistochemical examination. CONCLUSION: Early biopsy plays a critical role in establishing a definitive diagnosis for OMM. Histology combined with immunohistochemistry is the gold standard for diagnosing of hypomelanotic OMM.