Papillary Pattern in Acinic Cell Carcinoma of Parotid Gland: A Potential Diagnostic Pitfall on FNAC.

Fine needle aspiration cytology (FNAC) is often the first investigation in the work up of salivary gland lesions. However, its diagnostic accuracy is limited by the high rates of false positives and false negatives. Usually, acinic cell carcinoma is prone to be underdiagnosed because of the cytological similarity of the tumor cells to normal acinar cells, however rarely, a predominant papillary architecture on cytology may cause confusion with adenocarcinomas. We present a case of a 45-year-old male with a painful swelling of the right parotid region. FNA smears revealed a predominant papillary architecture and focal acinar pattern. A provisional diagnosis of acinic cell carcinoma was given, which was confirmed on histopathology. Familiarity with the cytomorphologic features of acinic cell carcinoma is cardinal for an accurate diagnosis and appropriate management.