Endoscopic ultrasound-guided fine needle aspiration of the pancreas: cytomorphological evaluation with emphasis on adequacy assessment, diagnostic criteria and contamination from the gastrointestinal tract.

OBJECTIVE Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been proved to be safe, efficient and reliable in the diagnosis of pancreatic lesions. This study evaluated specimen adequacy, diagnostic criteria of various pancreatic neoplasms and contamination from the gastrointestinal (GI) tract. METHODS EUS-guided FNA of the pancreas and subsequent surgical resections performed at the University of California Irvine Medical Center during February 1996-October 2000 were retrospectively selected. Modified Papanicolaou staining method was used for immediate evaluation and cell block prepared. RESULTS A total of 267 cases were available for review, including 147 (55.1%) positive/suspicious, 10 (3.7%) atypical, 96 (36.0%) negative and 14 (5.2%) unsatisfactory cases. Eighty-six (58.5%) positive/suspicious cases had histological confirmation and 12 (8.3%) had lymph node or distant metastases by cytology. Three atypical, two negative, and two unsatisfactory cases proved to have adenocarcinoma. Contamination from duodenum, stomach or pancreas was found in 77 positive/suspicious, three atypical and 90 negative cases. The sensitivity, specificity, diagnostic accuracy, positive and negative predictive values were 94.6%, 100%, 95.6%, 100%, 82% respectively. CONCLUSIONS EUS FNA is efficient and accurate in the diagnosis of pancreatic neoplasms in adequate samples. Contamination from the GI tract should be well recognized to avoid misinterpretation.