Biliary tract brush cytology

OBJECTIVE: To prospectively review brush smears obtained during endoscopic retrograde cholangiopancreatography (ERCP) primarily from the biliary tree. STUDY DESIGN: A total of 175 specimens from 147 patients were included in the study. The smears, prepared directly from the endoscopic brush, were stained by the Papanicolaou technique and analyzed for standard cytologic features. RESULTS: The smears were categorized into benign/reactive, significant atypia and suspicious/positive. The consistent features seen in suspicious or positive smears were tightly cohesive, small, three-dimensional cell clusters that formed cell balls. The cells in the clusters displayed features of malignant cells. CONCLUSION: ERCP-guided brushing is a safe diagnostic procedure for the evaluation of biliary tree lesions. Small, three-dimensional epithelial clusters with marked atypia signify malignancy and warrant the diagnosis of a malignant neoplasm even when only one or two such clusters are seen in the smears. Single cells, cytoplasmic vacuoles and prominent nucleoli are not essential for a diagnosis of malignancy.