Pathomorphologic, biochemical, and diagnostic aspects of gastrinomas (Zollinger-Ellison syndrome)

Morphology and immunohistochemically-defined endocrine function of pancreatic islet cell tumours

Thirty pancreatic islet cell tumours were histologically classified and analysed for their possible peptide hormone content using the immunohistoperoxidase method. Seven tumours contained insulin, six tumours contained gastrin and eight tumours contained glucagon. One tumour contained all three hormones. In the insulin and gastrin-containing tumours, the cells were usually arranged in solid nests of cells, with tubular and acinar formations in about half the cases. In the glucagon-containing tumours the cells were mainly arranged in anastomosing ribbons consisting of one of two layers of small cells. Most of the hormone-containing tumours were argyrophilic using Grimelius' silver reaction. All but one of the glucagon-containing tumours were incidental findings at autopsy. About half of the other tumours had metastasized. It is concluded that a relation exists between the histological pattern of growth and immunohistochemically defined endocrine function of pancreatic islet cell tumours.

Hypergastrinemia of antral origin in duodenal ulcer

A case of recurrent duodenal ulcer, basal gastric hypersection, and hypergastrinemia of antral origin is presented. The diagnosis was suggested preoperatively by stimulation tests with secretin and food. Billroth II antrectomy led to normalization of serum gastrin within half an hour. The gastrin content of the antral mucosa was not increased, neither was antral G-cell hyperplasia demonstrable. Postoperatively the basal gastric acid output and fasting serum gastrin levels were normal, without a postprandial increase in serum gastrin concentrations. The case does not support the existence of a specific disease called antral G-cell hyperplasia.

Endocrine pancreatic tumors

The pathology and cell biology of endocrine pancreatic tumors are reviewed. It is probable that all these tumors are "functioning" in the sense that they elaborate hormones that cause more or less conspicuous clinical syndromes. Identification of such secretory products is essential for an optimal diagnosis, localization, treatment, and follow-up. Recent data indicate that endocrine pancreatic tumors evolve from progenitor cells of ducts. This histogenetic mechanism may explain the occurrence not only of mixed or multihormonal tumors but also of tumors producing hormones that are absent from the adult human pancreas. In addition to their clinically apparent effects, many endocrine pancreatic tumors affect the surrounding endocrine pancreas in a characteristic way. The mechanisms behind and the potential diagnostic usefulness of these changes are discussed.

Serum gastrin response to acute and chronic hypercalcaemia in man: studies on the value of calcium stimulated serum gastrin levels in the diagnosis of Zollinger-Ellison syndrome

In this study the effect of calcium infusion over 3 h without gastric aspiration on serum gastrin was determined in fifteen normal subjects, ten patients with duodenal ulcer, nine with stomal ulcer, five with total gastrectomy, six with achlorhydria and sixteen with proved or presumed Zollinger-Ellison (ZE) syndrome. Serum gastrin only rose significantly in the patients with ZE-syndrome or achlorhydria. An increase of above or below 50% of basal value seems to be a valuable criterion by which to differentiate between patients with and without ZE-syndrome. Serum gastrin levels in forty-four patients with chronic hypercalcaemia (72+/-24 pg/ml, mean+/-SD) were not significantly different from the levels in 100 normal subjects (66+/-18 pg/ml; P greater than 0.10). However, in one patient with ZE-syndrome and in two patients with achlorhydria serum gastrin values were markedly higher during chronic hypercalcaemia than during normocalcaemia. It is concluded that acute or chronic hypercalcaemia without gastric aspiration does not lead to hypergastrinaemia in the absence of ZE-syndrome or achlorhydria.

The endocrine cells of the pancreas and related tumours. Ultrastructural study and classification

Up to seven endocrine cell types have been identified ultrastructurally in the pancreas, including glucagon A cells, insulin B cells, somatostatin D cells, pancreatic peptide F cells and 5-hydroxytryptamine EC cells. In addition, D1 cells, which have been proposed as the cell type producing VIP and possible P cells of unknown function are seen. Various patterns of endocrine cell differentiation have been found in 20 endocrine pancreatic tumours. Well and poorly differentiated B cells have been identified in 6 insulinomas, diagnostic G cells in 3 out of 7 gastrinomas, D1 and/or F cells in 7 diarrheogenic tumours. Moreover, cells apparently unrelated to the prevalent clinical syndrome have been noted in 8 of the 20 tumours. Granular non diagnostic cells (poorly diagnostic gastrin cells? D1 cells?) were particularly frequent in gastrinomas; agranular or poorly granular cells, either by "active" or "Stem cell" type, were present in nearly all tumours, particularly in diarrheogenic tumours, gastrinomas and malignant insulinomas. A cytological classification of pancreatic endocrine tumours is proposed.

"Somatostatinoma": a somatostatin-containing tumor of the endocrine pancreas

We studied the pancreatic and enteric hormone profile of a 46-year-old woman who had hyperglycemia and a pancreatic tumor. Before operation, there was no evidence of overproduction of glucagon or insulin. The tumor's ultrastructure had a distinctive endocrine morphology, resembling D cells. Prompted by the recent demonstration of somatostatin in D cells of pancreatic islets, we analyzed the tumor and found a large quantity of immunoreactive somatostatin (301 ng per milligram of tissue). Insulin, glucagon, gastrin, vasoactive intestinal polypeptide and human pancreatic polypeptide were present in only trace quantities. The tumor cells were cultured in monolayers, which remained viable up to 51 days and released somatostatin into the culture medium. In seven insulinomas and two glucagonomas, we found the somatostatin content either much lower (less than 0.6 ng per milligram of tissue) or undetectable. After complete resection of the tumor, our patient became euglycemic and has remained so for the past 20 months.

Morphology and staining patterns of endocrine cell tumours in the gut, pancreas and bronchus and their possible significance

We have studied 109 endocrine cell tumours of the gastrointestinal tract, pancreas and bronchus in terms of histological pattern and histochemical staining with immunocytochemical studies on seven tumours. As a result we believe that previous histological classifications need modification. 5-Hydroxytryptamine secreting tumours have a carcinoid (A1) pattern with, in some cases, an additional tubuloacinar element (A1A2) and definable histochemical reactions; well differentiated gastrinomas, insulinomas and glucagonomas are associated commonly, but not exclusively, with particular histological patterns and argyrophilia, but no such association exists for less differentiated tumours. This may be related to the synthesis of precursor hormones by less differentiated tumours. Mixed patterns are common, particularly in tumours of foregut derivation. Prospective studies planned to correlate histology, histochemistry, immunocytochemistry and ultrastructure are needed on all endocrine cell tumours.

Lowering of fasting and food stimulated serum immunoreactive gastric inhibitory polypeptide (GIP) by glucagon

The effect of intravenous glucagon infusion on serum levels of immunoreactive GIP (IR-GIP), insulin (IRI), gastrin (IRG), and on blood glucose has been investigated in six healthy volunteers in the fasting state and during ingestion of a mixed standard meal. Glucagon (500 ng/kg/min) lowered significantly serum levels of IR-GIP and IRG below the fasting values and increased the levels of IRI and blood glucose. Glucagon (50 ng/kg/min) infused 30 minutes before and continued 90 minutes after ingestion of a test meal abolished the IR-GIP response, suppressed significantly the IRG response, and left the IRI response unchanged. The same glucagon dose infused 60 minutes after ingestion of the test meal decreased significantly the raised levels of IR-GIP and IRG to fasting levels without changing IRI values. It is concluded that exogenous glucagon inhibits Gip release at the level of the GIP-producing cells.

Histologic characteristics of insulinomas and gastrinomas. Value of argyrophilia, metachromasia, immunohistology, and electron microscopy for the identification of gastrointestinal and pancreatic endocrine cells and their tumors

In a first step of our investigation the staining characteristics, especially the argyrophilia and metachromasia, of immunohistologically identified endocrine cells of the pancreatic islets and of the gastroduodenal mucosa were tested. These staining characteristics were then examined on insulinomas and gastrinomas. Contrary to normal B cells which generally react positively with aldehyde fuchsin and pseudoisocyanine but not argyrophilic with the Grimelius method, the neoplastic B cells give inconsistent results with conventional staining methods. Yet neoplastic B cells often show argyrophilic structures. Immunohistologically, most benign insulinomas are rich in insulin-containing cells, whereas in malignant types such cells are rare. The carcinomas, however, show a typical and distinct Grimelius argyrophilia. The tumor cells of gastrinomas are Grimelius argyrophilic and slightly metachromatic, as normal G cells, yet, contrary to A1 cells, they are only exceptionally stainable with the Hellerström method. Despite the great number of Grimelius positive tumor cells, generally only a few reacted with antigastrin serum. Nevertheless, the immunohistology is the most reliable method for the diagnosis of gastrinomas. Electron microscopic results are often difficult to interpret, since gastrinomas, as well as undifferentiated or malignant insulinomas, may predominantly contain atypical secretion granules.

Spontaneous Pancreatic beta cell tumor in the rat. A light and electron microscopic study

Fine structural study of a pancreatic neoplasm found at autopsy of a 27-month-old female Long-Evans rat showed that the tumor consisted of, and derived from beta cells of the islets of Langerhans.

Pancreatic polypeptide - a postulated new hormone: identification of its cellular storage site by light and electron microscopic immunocytochemistry

A peptide, referred to as pancreatic polypeptide (PP), has recently been isolated from the pancreas of chicken and of several mammals. PP is thought to be a pancreatic hormone. By the use of specific antisera we have demonstrated PP immunoreactivity in the pancreas of a number of mammals. The immunoreactivity was localized to a population of endocrine cells, distinct from the A, B and D cells. In most species the PP cells occurred in islets as well as in exocrine parenchyma; they often predominated in the pancreatic portion adjacent to the duodenum. In opossum and dog, PP cells were found also in the gastric mucosa. In opossum, the PP cells displayed formaldehyde - induced fluorescence typical of dopamine, whereas no formaldehyde-induced fluorescence was detected in the PP cells of mouse, rat and guinea pig. Also in these latter species, however, PP cells appear to possess amine-handling properties, a feature common to many peptide hormone-producing cells. The ultrastructure of the PP cells was defined by combining immunohistochemistry of semi-thin plastic sections with electron microscopy of adjacent ultrathin sections. PP cells show the ultrastructural features of peptide hormone-secreting cells. The PP cells of cat and dog contain fairly large, rather electron-lucent granules, and are probably identical with the previously described F cells. The PP cells of rat, guinea-pig, chinchilla and man contain small, fairly electron-dense granules. In these latter species no F cells are found. By immunoperoxidase staining of ultrathin sections, the PP immunoreactivity was found to be localized to the cytoplasmic granules. These observations provide support for the view that PP is a true pancreatic hormone.