Nondiagnostic fine-needle aspirates of the pancreas: A root cause analysis.

Material related errors contributed to the majority of nondiagnostic results and were primarily related to fibrotic cancers, chronic pancreatitis, absence of diagnostic criteria of cystic lesions, and technically challenging cases. Only 1 major interpretation error was identified. Sampling and interpretive errors contributed equally to man-related causes. For mucinous cysts, neoplastic mucin was difficult to identify in liquid-based preparations. Pathologists tended to issue a nondiagnostic categorization when epithelial cells are lacking and particularly when the nature and radiological impression of the cyst was not communicated.