Fine-needle aspiration cytology of mammary analog secretory carcinoma masquerading as low-grade mucoepidermoid carcinoma: Case report with a review of the literature

摘要

Background/Aim: The primary role of fine-needle aspiration cytology (FNAC) of salivary gland masses is to determine the underlying process and guide further management. The objective of our study is to provide a comprehensive review of cytologic features and ancillary studies of mammary analog secretory carcinoma (MASC), discuss differential diagnosis and review recent advances in the understanding of its biologic behavior. Case: A 23-year-old female underwent ultrasound-guided FNA of a slowly enlarging parotid mass. Smears displayed branching clusters of bland vacuolated polygonal cells in a secretory proteinaceous background. Eosinophilic cells with eccentric nuclei and inconspicuous nucleoli were also noted. Based on positive intracellular mucin staining and the lack of extracellular-matrix material, the cytologic diagnosis rendered was 'suspicious for low grade mucoepidermoid carcinoma'. Superficial parotidectomy revealed an MASC confirmed by fluorescence in situ hybridization (FISH) studies for ETV6 translocation. Conclusion: MASC should be included in the differential diagnosis of mucinous salivary lesions with cystic changes on FNA. Immunohistochemistry for mammaglobin and S-100 helps in excluding morphologic mimics. FISH helps to confirm the diagnosis. Age alone should not be a deterrent in diagnosing a carcinoma.