Mucoepidermoid carcinoma of unknown primary in the head and neck: a case report and review of the literature

OBJECTIVE: Mucoepidermoid carcinoma of unknown primary (MEC-UP) in the head and neck is a rare presentation of the most common salivary gland cancer. Cancers of unknown primary sites often have poorer prognoses than similar cancers with known primary. Few cases of MEC-UP have been reported; therefore, the objective of this report is an overview of the diagnosis and management of MEC-UP. METHODS: We present two patients with low-grade MEC-UP at a high-volume tertiary care institution in Ontario, and a database search returning 1560 citations of which five studies with seven MEC-UP cases were identified. RESULTS: Review of the limited cases suggest many clinicians use positron emission tomography-computed tomography (PET-CT) in addition to panendoscopy and targeted biopsies with consideration for diagnostic tonsillectomy in diagnostic work-up. CONCLUSION: Like other salivary gland cancers, primary therapeutic surgical resection is recommended with low threshold for adjuvant radiotherapy to regions at high risk for harbouring the primary malignancy, especially in cases of high-grade histopathology.