Warthin-Like Secretory Carcinoma of the Parotid Gland: A Diagnostic Pitfall in Fine Needle Aspiration Cytology.

Secretory carcinoma (SC) of the salivary gland, previously known as mammary analog SC, is a rare malignant neoplasm characterized by ETV6 gene rearrangements that most commonly arises in the parotid gland of middle-aged to older adults. Several salivary gland neoplasms harbor a prominent lymphoid component, most classically Warthin tumor; however, SC is rarely associated with this feature. We present a case of a Warthin-like secretory carcinoma with robust tumor-associated lymphoid proliferation (TALP) in the parotid gland of a 69-year-old Caucasian male with a 30-pack-year smoking history. Fine needle aspiration (FNA) cytology demonstrated oncocytic-appearing epithelial cells in a lymphocyte-rich background with cystic debris, closely mimicking the cytomorphology of Warthin tumor. The subsequent parotidectomy revealed an epithelial neoplasm with mixed solid, cribriform, and cystic architecture, abundant eosinophilic luminal secretions, and robust TALP. Immunohistochemical studies on the resection specimen confirmed Warthin-like secretory carcinoma. ETV6-NTRK3 fluorescence in situ hybridization was not performed, as the combined histomorphologic and immunohistochemical profile was considered diagnostic. This underrecognized variant poses a significant diagnostic pitfall, as overlapping morphologic features may lead to misclassification as Warthin tumor on cytology.