Mucosal melanoma of oral cavity (MMO) is a relatively rare tumour comprising of 40% of all head and neck mucosal melanomas. This study assessed the treatment outcomes and factors affecting prognosis in oral cavity mucosal melanomas. The clinical case records of 25 cases of oral cavity mucosal melanomas treated in our institution during 2003-2013 were retrospectively reviewed. Various clinicopathological parameters were taken into consideration and statistical analysis done by Kaplan-Meier method and Cox's proportional hazards model. The most common sites of MMO were upper alveolus and hard palate (64%) followed by lower alveolus (28%). 57.1% mucosal melanomas of hard palate and upper alveolus had associated metastatic lymph nodes whereas all cases of MMO of lower alveolus had lymph node metastasis. Disease failure at distant sites was higher than that at primary site or lymph nodes. The most common site of distant metastases was brain. The 5-year OS for treated cases was 23.8% and among subsites, MMO of hard palate and upper alveolus had the highest survival. Metastasis to lymph nodes and bone infiltration by tumour significantly decreased the survival. Recurrence at primary site had the worst prognosis. MMO with lymph nodal involvement and bone erosion had poor prognosis. Due to high chances of lymph node metastases and disease recurrence in lymph nodes following treatment, it is essential to do an elective neck dissection for all cases of MMO. Disease failure at primary site was an independent predictor of outcome in MMO.
Keywords: Head and neck; Mucosal melanoma; Oral cavity.
© Association of Otolaryngologists of India 2020.