Unusual pancreatic tumor resembling solid and cystic tumor, with somatostatin production and aberrant crystalloid structures.

An unusual pancreatic tumor in a middle-aged man is reported. The tumor was a large encapsulated mass with necrosis and hemorrhage, and microscopically, it showed a predominant microcystic pattern with solid pattern areas. The clinical and histological features of this tumor were similar to those of solid and cystic tumor. Immunohistochemical studies showed that the tumor was positive for alpha 1-AT, NSE, CA 19-9 and somatostatin. Electron microscopy studies showed neurosecretory granules, intercellular junctions, annulate lamellae and aberrant crystalloid structures. These findings indicated that the tumor had differentiated into acinar, ductal and endocrine cells, suggesting that solid and cystic tumor originates from multipotential immature cells.