Full pancreatic endocrine differentiation in a mediastinal teratoma.

In a mediastinal teratoma containing pancreatic tissue rich in islet cells, immunofluorescence studies showed a high degree of differentiation of the endocrine tissue. Insulin-, glucagon-, somatostatin-, and pancreatic polypeptide(PP)-containing cells were all consistently represented. They showed the same precise topographic distribution that is seen in normal islets (i.e., a central core of insulin-containing cells with the other cell types in a peripheral position) and that is thought to be important for the integrated function of the islets. This may explain the absence of clinical symptoms of hypoglycemia. In addition, a nonrandom distribution of endocrine cell types, with PP-rich and PP-poor areas, similar to that found in pancreatic regions embryologically derived from the ventral and dorsal anlagen, respectively, was observed. This finding suggests that the unknown mechanisms responsible for the dissimilar endocrine cell contents in pancreatic regions of different embryologic origins were operating in the teratoma.

Multiple islet cell tumors with predominance of glucagon-producing cells and ulcer disease.

Two cases of multiple islet cell tumors mostly composed of glucagon-producing cells and associated with severe ulcer disease are presented. Multiple endocrine neoplasia type I (MEN-I) was present in both patients, although symptomatically latent in case 2. Immunohistochemistry showed that glucagon (A) cells were a major cell population (i.e., accounting for at least 30% of the tumor cell population) in 24 of 43 tumors (either macroadenomas or microadenomas) studied in case 1 and in 12 of 17 tumors studied in case 2. A major pancreatic polypeptide (PP) cell population was found in 12 and 7 tumors of case 1 and 2, respectively. In contrast, insulin (B) and somatostatin (D) cells were scarce in most adenomas. Gastrin-producing cells were not identified in any tumors, despite the use of different antigastrin antisera. Extrapancreatic or residual gastrinomas were not found at postmortem examination in case 1 or on appropriate surgical inspection done 24 years after the onset of the ulcer disease in patient 2. On the basis of these and of 17 additional cases collected in the literature, it is concluded that multiple A-cell tumors of the pancreas are an expression of the MEN-I and are mostly associated with ulcer disease and/or with hypergastrinemia of frequent uncertain origin. The mechanisms regulating the nonrandom phenotypic hormonal differentiation of these genetically determined tumors remain unknown.

[Cholelithiasis in childhood. Case study contribution]. / La colelitiasi in età pediatrica. Contributo casistico.

Two cases of cholesterinic cholelithiasis in paediatric age are reported and the literature on the subject reviewed.

Pathology of endocrine cells in gastric mucosa.

Pathological changes of gastric endocrine cells are reviewed. The lesions are subdivided according to the type of mucosa in which they originate. Hyperplasias of fundic endocrine cells, probably related to the patient's concomitant hypergastrinemia, were found in Zollinger Ellison syndrome and in chronic atrophic gastritis. They may evolve into carcinoid tumors. Typical and atypical forms of fundic carcinoids have been described, usually without specific clinical syndrome. Antral gastrin G cells proliferate in achlorhydric, hypergastrinemia patients while their involvement in peptic ulcer disease is probably limited to a minority of cases. Antral gastrin secreting tumors are rare. Metaplasic intestinal epithelium also harbors endocrine cells that may present hyperplastic and neoplastic changes.

Histologic, immunofluorescence, and ultrastructural study of malignant islet-cell tumors of the pancreas induced in hamsters by BK human papovavirus.

Histologic, immunofluorescence and ultrastructural studies were performed in 17 cases of pancreatic carcinomas induced by the BK virus in Syrian hamsters, a unique model of experimentally induced malignant islet cell tumors. The tumors were composed of small, poorly differentiated cells mostly arranged in a trabecular structure. By immunofluorescence all four islet cell types were found in the tumors, though with different frequency. Insulin cells were present in 16 cases, glucagon cells in 11, somatostatin cells in 7, PP cells in 6. Thirteen tumors contained more than one cell type. Insulin cells were the most frequent cell type in 13 cases, and glucagon cells predominated in 1 case. Insulin-containing cells usually occupied a central position within tumor-cell aggregates, while the other cell types were mostly located in a peripheral position, a distribution reminiscent of that seen in normal islets. Gastrin and calcitonin immunoreactivities were not observed. Immunoreactive cells were more abundant in tumors with trabecular structure. Argyrophil cells revealed by the Grimelius method often exceeded the cumulative number of immunoreactive cells in the same tumor, which suggests that there were additional cell types. Multiple cell types were also found in liver metastases. Ultrastructurally most neoplastic cells were poorly granulated. The occurrence of many damaged cells suggests hormone leakage, which may account, at least in part, for the deregulated hormone release from the tumors.

Simultaneous polypoid tumors of the stomach and duodenum with composite cell population (mucous, argyrophil, and lysozyme-containing cells): a case report.

Seventeen years after a Billroth II gastric resection for duodenal ulcer had been performed, two large polypoid tumors were found in the gastric stump (outside the stomal area) and in the duodenal stump of a 69-year-old man. Histologically the neoplasms were tubular adenomas with small focal carcinomatous changes restricted to the gastric tumor. A distinctive feature of both tumors was the occurrence of three major cell populations segregated into two different types of neoplastic epithelium: one with columnar mucous cells containing gastric type mucins and mixed with a large number of argyrophil endocrine cells and the other with large, pleomorphic cells containing immunoreactive lysozyme and intestinal type mucins. In the absence of any evidence of generalized gastrointestinal polyposes, it is suggested that both tumors originated from the gastric mucosa (of heterotopic origin in the duodenum) and that the second type epithelium may represent a particular, and up to now unrecognized, type of intestinal metaplasia.