Acinar cell carcinoma of the pancreas: clinical and cytomorphologic characteristics.

Acinar cell carcinoma is a rare malignant epithelial neoplasm with predominantly exocrine acinar differentiation and is seen primarily in older men (mean age, 62 years). The presenting symptoms are usually non-specific, and jaundice is often not present. Symptoms relating to the overproduction and release of lipase into the circulation are present in 10-15% of patients. Characteristic cytomorphologic features include a population of cells with minimal pleomorphism, eccentrically placed nuclei with a single prominent nucleoli and moderate hyperchromasia. The cytoplasm is finely granular, and the background may contain granular debris secondary to cytolysis. A significant proportion of the cases also have a minor neuroendocrine component or scattered neuroendocrine cells. Approximately 50% of patients have metastatic disease at presentation, often restricted to the regional lymph nodes and liver. The prognosis is poor, only slightly better than that of pancreatic ductal adenocarcinoma.