Pancreatic solid and cystic hamartoma in adults: characterization of a new tumorous lesion

Nonneoplastic tumor-like lesions ("pseudotumors") of the pancreas include cystic and noncystic varieties. We report on a solid and cystic tumor-like lesion of the pancreas that occurred in 2 adult patients. The lesions, located in the head and neck of the gland, respectively, were well demarcated and composed of cystic ductal structures embedded in focally inflamed stromal tissue. In addition, one of the lesions showed irregularly arranged but well-differentiated acini and small intralobular and interlobular ducts embedded in hypocellular, fibrotic tissue. Discrete islets were lacking, but immunohistochemical staining for chromogranin A revealed individual scattered endocrine cells evenly distributed between acinar and ductal cells. The surrounding pancreatic parenchyma did not show significant chronic pancreatitis. After tumor removal, the follow-up of the patients was uneventful. Because of the irregular arrangement of otherwise mature tissue components of the pancreas, the lesions were considered solid and cystic hamartomas. Their pathogenesis is so far unknown.