Clinicopathological studies on solid and cystic tumors of the pancreas.
Three cases of pancreatic tumor in two females (case 1, case 3) and one male (case 2) were reported. Macroscopically cases 1 and 3, which were surrounded by a thick fibrous capsule, developed toward the outside of the pancreas and the cut surface showed mainly cystic degenerative areas filled with necrotic and hemorrhagic materials. In contrast with these two cases, case 2 was buried in the pancreatic tissue and the cut surface showed cystic degenerative areas in its center with a thick fibrous capsule and tumor cell nests invading beyond the capsule to the parenchyma of the pancreas. Microscopically each tumor was identical. The solid areas on the periphery were composed of sheets of polygonal uniform cells subdivided by delicate fibrovascular stalks. Near the degenerative areas, tumor cells lay on a delicate fibrovascular core in one or two layers, with pseudopapillary patterns. Mitotic figures were very rare. All three cases demonstrated immunoreactivity for alpha-1-antitrypsin, but not for islet hormones, tumor markers nor neuron-specific enolase. Although electronmicroscopically, zymogen granules were detected in cases 2 and 3, and annulate lamellae in cases 1 and 3, ductal cell character features were not so developed. From the above, these tumors were diagnosed as solid and cystic tumors of the pancreas. Furthermore, it was suggested that they differentiated in the direction of acinar cells.