Basic cytomorphology of pancreatic lesions

In patients with a palpable or radiologically identified pancreatic lesion, FNA is a safe and accurate procedure for procuring diagnostic material. Complications of the procedure are rare, and the morbidity and mortality are considerably less than that associated with open laparotomy and wedge biopsy. The most common complication associated with pancreatic FNA is acute pancreatitis. Contraindications to FNA include an uncorrectable bleeding diathesis, and marked ascites. The accuracy of FNA for diagnosing pancreatic adenocarcinoma is about 90%, and the overall sensitivity can be increased by multiple needle passes. Close communication and collaboration among the clinician, radiologist, and pathologist can help assure that suitable tissue is obtained and maximize the diagnostic yield of the procedure. To this end, the presence of the pathologist or a cytotechnologist at the FNA procedure is desirable to assess the tissue as it is procured. The vast majority of malignant pancreatic neoplasms are ductal adenocarcinomas. Thus, the primary diagnostic problem facing the pathologist is differentiating adenocarcinoma from benign and/or inflammatory processes. The three key cytologic features that aid in this distinction are anisonucleosis, increased nuclear size, and nuclear molding. When all three of these features are present, the sensitivity of the procedure approaches 98%, and its specificity approaches 100%. The article describes the cytomorphology of the more common lesions of the pancreas.