Warthin-like Mucoepidermoid Carcinoma in an Elderly Male Patient: A Case Report

Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy, yet its "Warthin-like" variant (WL-MEC) remains an exceptionally rare entity with approximately 80 cases reported since its formal naming in 2015.

We present a case of a 71-year-old male with a 2'2 cm painless right parotid mass. Histological evaluation of the resected cystic tumor revealed a complex architecture of mucinous, intermediate, and atypical epidermoid cells interspersed with regions of bilayered oncocytic epithelium and dense lymphoid stroma with germinal centers. While the focal presence of organized bilayered epithelium posed a diagnostic challenge by mimicking a WT, immunohistochemistry demonstrated p40 and p63 positivity throughout the squamoid and intermediate cell populations. Definitive diagnosis of WL-MEC was established via FISH analysis, which confirmed a MAML2 gene rearrangement. This case is clinically significant as it occurred in an elderly male, contrasting with the typical female predilection and younger age distribution associated with this variant.

Ultimately, the diagnosis of WL-MEC requires high clinical suspicion and the integration of molecular testing to differentiate it from metaplastic Warthin tumors, ensuring appropriate diagnosis and management for this generally indolent but morphologically deceptive neoplasm.