Predictors of Nodal Metastasis in Mucoepidermoid Carcinoma of the Oral Cavity and Oropharynx.

Introduction: Mucoepidermoid carcinoma (MEC) of the upper aerodigestive tract (UADT) is an uncommon malignancy, with limited literature available on its clinical and pathologic characteristics. Here, we describe the behavior of MEC of the UADT including pathologic characteristics and predictors of nodal metastasis.

Methods: Retrospective cohort study of patients with MEC of the UADT treated at an academic medical center from January 2008 to May 2018. Data was collected about demographics and tumor characteristics including clinical and histological data. The two-tailed Student t test and χ2 analysis were performed to assess for predictors of nodal metastasis.

Results: We identified 44 patients with minor salivary gland MEC of the oral cavity (OC) and oropharynx (OP). All patients were treated with primary site surgery. The primary site was the OC in 25 patients (57%) and OP in 19 (43%). Low-grade histology was seen in 27 specimens (61.4%), intermediate histology in 9 specimens (20.5%), and high-grade histology in 8 specimens (18.2%). Perineural invasion was noted in 10 specimens (22.7%). Neck dissection was performed in 17 patients (39%), with pathologically positive nodes found in 9 (20.5%). Notably, 5 of the 9 positive nodal specimens were found in clinically node-negative necks. Pathologically positive cervical lymph nodes were significantly associated with the OP as the primary site (p = 0.0005), perineural invasion (p = 0.012), lymphovascular invasion (p < 0.001), and high-grade histology (p = 0.004) in the primary specimen.

Discussion: MEC of the UADT is an uncommon malignancy. Our findings suggest elective neck dissection should be considered with perineural and lymphovascular invasion, high-grade tumor, and the OP as the primary site.