MAML2 negative oncocytic mucoepidermoid carcinoma of submandibular gland

Abstract

BackgroundOncocytic mucoepidermoid carcinoma is a rare variant of mucoepidermoid carcinoma. Only a few cases are reported involving mostly the parotid gland with only four cases reported in the submandibular gland. Mastermind-like 2 (MAML2) translocation is detected in about 66% mucoepidermoid carcinoma and many oncocytic mucoepidermoid carcinoma.Case presentationWe present a rare case of MAML2 negative oncocytic mucoepidermoid carcinoma of the submandibular gland in a 73-year-old female. CT revealed a large left submandibular gland mass. Submandibular gland resection with marginal mandibulectomy and ipsilateral neck dissection was performed. Grossly, a solid-cystic submandibular gland tumor was identified. Microscopic examination revealed an infiltrative proliferation of oncocytes. Foci of squamoid and intermediate cells with rare mucocytes were present. Two ipsilateral cervical lymph nodes and mandible were involved. Immunohistochemistry and special stains demonstrated positivity for p63, p40, CK5/6, mucicarmine and alcian blue. No MAML2 gene rearrangement was identified.ConclusionAn awareness that MAML2 negative mucoepidermoid carcinoma exists will prevent misdiagnosis and incorrect treatment as many of its differential diagnoses are benign.