Extensive Regional Metastasis of High-Grade Mucoepidermoid Carcinoma of Unknown Primary

Publication date: Available online 15 December 2016
Source:Journal of Oral and Maxillofacial Surgery
Author(s): Naseem Ghazali, Alyssa Flashburg, Robert A. Ord
PurposeMucoepidermoid carcinoma (MEC) is the commonest salivary carcinoma. It arises most frequently in major salivary glands but may arise in minor glands or intraosseous sites. MEC of unknown primary very rarely occurs. This report documents only the third case in the medical literature.MethodsA 66-year old man with previous carcinoma-in-situ (CIS) of the left posterior oral tongue that was excised in 2004 and also in 2010, presented with a hard node 3x2 cm at level II of the right neck in July 2015. PET/CT revealed multiple, bilateral cervical lymphadenopathy, with no primary site identified. FNAB/Cytology from the right neck was positive for malignancy, suggestive of metastatic squamous cell carcinoma (SCC). Panendoscopy/biopsy revealed CIS at the tongue bases and tonsils bilaterally (p16-negative). The patient was presented to a tumor board and definitive concurrent cisplatin-based chemoradiation was recommended for TisN2cM0, Stage IVA oropharyngeal CIS and was completed in November 2015. PET-CT in January 2015 showed complex interval changes, with some areas demonstrating improvement (i.e. no uptake in left neck) and worsening in others (i.e. increased metabolic activity in right neck), suggestive of residual disease. Repeat PET/CT in March 2016 showed increased nodal involvement and increasing SUV. Bilateral modified radical neck dissection was undertaken and histology showed High-grade MEC in 51/61 nodes with extracapsular spread and soft tissue involvement.ResultsPatient died May 2016 two months post-surgery.
ConclusionsMetastatic MEC of unknown primary is a diagnostic challenge. PET-CT may not be the most reliable diagnostic investigation to identify the primary or metastatic foci as demonstrated in this case.



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