Morphogenesis of pancreatoblastoma, infantile carcinoma of the pancreas: report of two cases.

Two cases of infantile carcinoma of the pancreas were diagnosed as pancreatoblastoma based on the morphogenesis of the tumors. These encapsulated tumors adhered to the head of the pancreas and to the descending portion of the duodenum. Histologic examination revealed an organoid structure made up of cords or nodules of squamoid cells with elongated nuclei arranged in a parallel fasciculating pattern (squamoid corpuscles), surrounding tubular structures of columnar epithelial cells and intermediate light cell masses with little differentiation. Electron microscopy revealed zymogen-like granules and well developed granular endoplasmic reticulum in the cytoplasm. There were no detectable islet cells in tumor tissue. Both of these tumors could be derived from the ventral pancreas and be isolated by the lack of communication with the duct of Wirsung. As the duct of Santorini was patent, extirpation of these organoid tumors would not influence secretion of pancreatic juice. Considering the favorable prognosis after extirpation of these tumors, they should be differentiated from the usual adenocarcinoma of the pancreas occurring in adults.