Clinical Utility of Cytology with Ancillary Testing in the Management of Patients with Pancreaticobiliary Lesions

The cytological diagnosis of pancreaticobiliary (PB) lesions is fraught with challenges. Diagnostic specificity is high, but sensitivity suffers from a high threshold for a definitive diagnosis of malignancy. Ancillary testing using immunohistochemical stains, biochemical analysis and genetic testing have greatly improved diagnostic accuracy of cytology and small biopsy samples of PB lesions. This review of the cytomorphology and helpful ancillary tests for the diagnosis of the commonly encountered PB lesions offers a practical approach for the practicing pathologist.