The patterns of beta-cell regeneration in untreated diabetic and insulin-treated diabetic Syrian hamsters after streptozotocin treatment

Pleomorphic nonfunctioning islet cell tumor of the pancreas

A nonfunctioning islet cell tumor of the pancreas in a 68-yr-old female is reported. All of the laboratory data, including serum hormones, glucose, and tumor markers, were within normal limits. A pancreatoduodenectomy was performed. Cut sections of the specimen revealed a cystic mass measuring 6.0 x 4.5 x 3.5 cm. Histologically, the tumor consisted of large acidophilic cells with bizarre giant nuclei. The tumor cells were positive for chromogranin-A, synaptophysin, neuron-specific enolase, and S-100 protein. Multifocal proliferation of endocrine cells, centroacinar cells and changes in acinar cells were found in the adjacent uninvolved pancreatic tissue. Ultrastructural studies of the tumor revealed clear nuclei with no zymogen, but immature neurosecretory granules in the cytoplasm of the tumor cells. These findings were consistent with those of nonfunctioning islet cell tumors, especially of the pleomorphic type. To the best of our knowledge, this is the first report on pleomorphic nonfunctioning pancreatic islet cell tumors.

Solid and cystic tumor of the pancreas occurring without cyst formation in an adult male

A solid and cystic tumor (SCT) of the pancreas occurring in a 35-yr-old male is reported. Cut sections of the specimen revealed a solid, ill-defined mass measuring 2.5 x 2.3 x 2.0 cm, without cystic or necrotic changes. Histologically, the solid tumor consisted of small, round acidophilic cells invading the surrounding pancreatic parenchyma. The tumor cells were positive for alpha-1-antitrypsin and neuron-specific-enolase. Ultrastructural studies revealed clear nuclei with no zymogen, but immature secretory granules in the cytoplasm of the tumor cells, which had a junctional complex-like structure. These findings were consistent with the so-called solid and cystic tumor of the pancreas. There was neither a capsule surrounding the tumor nor a papillary structure, known to be characteristic findings of the SCT tumor. The small tumor reported in the present article might represent an early-stage SCT of the pancreas.