Percutaneous fine-needle aspiration cytologic study of main pancreatic duct stenosis under pancreatographic guidance. When pancreatography shows a stenosis of the main pancreatic duct in patients with normal or inconclusive ultrasound and computed tomography, the exact nature of such stenosis is sometimes difficult to precise before surgical exploration. In such cases, the authors systematically performed a percutaneous fine-needle aspiration cytologic study of the stenosis under pancreatographic guidance. Fifteen patients were referred because of suspected pancreatic malignancy. The tumor markers, carcinoembryonic antigen (CEA) and CA 19-9 were normal in 11 patients and elevated in one patient, whereas only CA 19-9 was elevated in three others. In 14 cases, both the ultrasound and computed tomography did not show any obvious pancreatic mass. The pancreatography was done through endoscopic retrograde cholangiopancreatography (ERCP) (12 patients) or percutaneously in case of failure at ERCP3 and showed a main pancreatic duct stenosis that underwent aspiration by percutaneous fine needle precisely positioned using biplane fluoroscopy. The aspirated material was then smeared on glass slides, air-dried, and stained by Giemsa. In nine of the 15 patients, cytologic study revealed adenocarcinoma. This was confirmed by surgery in five and by progressive deterioration followed by death in four. In six patients, cytologic study gave a nonmalignant result. Chronic pancreatitis was found in five of them, confirmed at surgery in three and based on uneventful follow-up of at least 12 months in two others. In one case, a pancreatic adenocarcinoma not detected by cytologic study was found at surgery. Thus, the sensitivity and specificity of this diagnostic approach were 90% and 100%, respectively. No serious complication was noticed. The authors conclude that when ultrasound and computed tomography are inconclusive, percutaneous fine-needle aspiration cytologic study of main pancreatic duct stenosis under pancreatographic guidance is a safe, simple, and helpful procedure in the investigation of patients with suspected pancreatic malignancy. 