Mucoepidermoid carcinoma of the base of the tongue: a case report and review of the literature.

[BACKGROUND] Mucoepidermoid carcinoma originates from reserve cells present in ducts of salivary glands and is the most common malignancy of the salivary glands. It is commonly found in the parotid gland, followed by the palatal and buccal mucous membranes. However, mucoepidermoid carcinoma occurrence in other intraoral sites, including the tongue base, is extremely rare.

[CASE PRESENTATION] A 33-year-old Chinese man presented with a progressively enlarging mass at the base of his left tongue. Contrast-enhanced computed tomography and magnetic resonance imaging revealed an augmented soft tissue mass in the left jaw region with indistinct boundaries, enlargement of cervical lymph node of uncertain etiology, and no evidence of distant metastasis. A transoral needle biopsy from the mass pathologically revealed low-grade mucoepidermoid carcinoma. Complete transoral excision and cervical lymph node dissection were performed, followed by reconstruction with an anterolateral thigh free flap. Examination of the obtained surgical specimen confirmed low-grade mucoepidermoid carcinoma with MAML2 gene fusion in the base of the tongue. The tumor was removed with negative margins, and the cervical lymph nodes were free of disease. The patient had an uneventful recovery and showed no evidence of recurrence or metastasis at 40 months of follow-up.

[CONCLUSION] We present a rare case of mucoepidermoid carcinoma at the base of the tongue. Furthermore, we review related literature and discuss its clinical features, histopathological characteristics, and treatment strategies.