The syndrome of gastric argyrophil carcinoid tumors and nonantral gastric atrophy

Composite carcinoid-adenocarcinoma of the stomach associated with multiple gastric carcinoids and nonantral gastric atrophy

A case of multiple gastric carcinoids and nonantral atrophic gastritis in which the larger tumor was a composite carcinoid-adenocarcinoma is presented. The two components of the composite tumor immunohistochemically showed clear-cut diverging functional differentiations although the available evidence supported a common histogenesis from the metaplastic intestinal epithelium of the gastric mucosa. The carcinoid tissue of the composite tumor, which showed "atypical" features, also differed from the other, pure carcinoids, in which the histologic appearance was "typical." Total gastrectomy performed 1 month after the original gastric resection with antrectomy disclosed regressive changes in the endocrine cell proliferations of the gastric stump consistent with the withdrawal of a stimulating effect of the antral gastrin.

The ratio of pepsinogen A to pepsinogen C: a sensitive test for atrophic gastritis

To diagnose fundic atrophic (type A) gastritis as part of the clinical investigation of various diseases or for epidemiologic purposes, a simple and reliable diagnostic test would be of great value. We studied circulating levels of pepsinogen A (PGA) and pepsinogen C (PGC) in 179 patients with fundic atrophic gastritis, 29 unselected patients with gastric adenocarcinoma, 15 totally gastrectomized patients, and 50 gastroscopically examined normal controls. Of 147 patients with severe atrophic gastritis, 42 (29%) had serum PGA and 22 (15%) serum PGC values within the range of those in totally gastrectomized patients. The most sensitive test for fundic atrophic gastritis was the PGA/PGC ratio in serum, the sensitivity and specificity being 99% and 94%, respectively (discrimination limit, 5.5). Correspondingly, the positive predictive value was 98%, and the negative predictive value 98%. Of 29 unselected patients with gastric adenocarcinoma 22 (76%) had serum PGA/PGC values lower than the discrimination limit for atrophic gastritis. We conclude that the relatively simple analysis of PGA and PGC in serum is a powerful test for fundic atrophic gastritis with several potential areas of application.

Circulating gastrin, endocrine cells, histamine content, and histidine decarboxylase activity in atrophic gastritis

Thirty-five patients with fundic atrophic gastritis and achlorhydria were classified in two groups according to the presence or absence of fundic argyrophil, mostly enterochromaffinlike cell hyperplasia. Among the biologic and histologic parameters studied, the hyperplasic group differed only by a circulating hypergastrinemia and an antral G-cell hyperplasia. The histamine content, the histidine decarboxylase activity, and the mast cell number of fundic biopsies were determined in 10 controls, 16 of the preceding patients (11 with and 5 without fundic argyrophil-cell hyperplasia), and 5 patients with fundic atrophic gastritis and neither achlorhydria nor hyperplasia. Histamine content and histidine decarboxylase activity were increased only in the hyperplasic group despite an unchanged mast cell number. For all fundic biopsies the argyrophil-cell density was positively related to the histamine content. Finally, the argyrophil-cell hyperplasia occurring in fundic atrophic gastritis with achlorhydria is associated not with the gastritis intensity, as assessed by histologic and secretory criteria, but with a circulating hypergastrinemia and an increase of both fundic histamine content and histidine decarboxylase activity.

Atrophic gastritis and gastric carcinoid tumours

During recent decades an increasing number of case reports have pointed at a relation between atrophic gastritis type A and gastric carcinoid. This relation has now been quantitatively documented in endoscopic screening studies. Among patients with pernicious anaemia the prevalence of gastric carcinoid was 2-9%. Many of these carcinoids, however, remain subclinical. The majority are broadbased polypoid tumours. Most are situated in the gastric body or fundus. Of 95 patients with atrophic gastritis and gastric carcinoid reported in the literature, 60 (63%) had multicentric tumours and 13 (14%) lymph node and/or hepatic metastases. Microscopically, the tumours, which are frequently of the enterochromaffin-like cell type, show various structural differentiations, glandular differentiation indicating malignant potential. Purely intramucosal carcinoids have been described. The precurser lesion to such "early carcinoids", as well as to infiltrating carcinoids, is probably hyperplasia of endocrine cells in the atrophic fundic mucosa. Such hyperplasias, whether nodular or diffuse, are quantitatively related to hypergastrinaemia, which is a typical feature of antrum sparing (type A) atrophic gastritis. Most tumours can be treated endoscopically, although antrectomy with abolition of hypergastrinemia may be the definitive treatment. It seems that the risk of developing gastric carcinoid 'per se' does not justify regular gastric screening in patients with type A atrophic gastritis. However, as these patients also run an increased risk of developing several benign diseases, gastric adenocarcinoma, and probably also pancreatic malignancy, regular survey in selected cases is indicated.

Gastrointestinal carcinoid tumours. Histogenetic, histochemical, immunohistochemical, clinical and therapeutic aspects

The increased knowledge of the pathobiology of gastrointestinal carcinoid (neuroendocrine) tumours and the improved therapeutic possibilities have brought a demand for more precise diagnosis. Although the carcinoid tumours can often be tentatively recognized in routinely processed microscopic slides, their more accurate identification requires additional diagnostic procedures. General neuroendocrine markers such as the argyrophil reaction of Grimelius and immunohistochemistry with application of antibodies against chromogranin A and of neuron-specific enolase are discriminatory staining methods which are used to reveal the neuroendocrine origin of almost all highly differentiated carcinoid tumours of the gastrointestinal tract. Mid-gut carcinoids, which predominate among these tumours almost unexceptionally contain serotonin. This biogenic amine can be demonstrated by the argentaffin reaction of Masson, serotonin immunoreactively or by formalin-induced fluorescence. The characteristic staining pattern of mid-gut carcinoids is almost invariably preserved in the metastatic deposits and consequently the staining methods for identifying serotonin can also be used on metastases to reveal a primary mid-gut carcinoid. The enterochromaffin-like (ECL) cell carcinoids of the body and fundic area of the stomach often seen in association with pernicious anaemia are argyrophil with the Sevier-Munger silver stain. Other neuroendocrine tumours, viz. antral, duodenal and rectal carcinoids should be studied by a battery of relevant peptide hormone antisera for adequate diagnosis. During the last decade new peptide hormones have been found in circulation in patients with carcinoid tumours, but serotonin and urinary 5-HIAA are still the most important markers for carcinoids of the mid-gut origin. Other clinically useful tumour markers are chromogranin A + B, pancreatic polypeptide, human chorionic gonadotropin alpha and beta subunits. For localizing procedures, angiography is the most reliable investigative method for primary tumours in the gut, whereas CT-scan and ultrasound investigations are good for detection of liver metastases. During the last five years, the therapy for malignant carcinoid tumours has been considerably improved. Chemotherapy has only revealed objective response rates in about 10-30% of the patients giving median survivals from start of therapy of about 10 months. Recently treatment with alpha interferons and the new somatostatin analogue octreotide have given objective responses in 50-75% of patients with malignant mid-gut carcinoid tumours. These patients have now a median survival from start of therapy of 70 months when treated with alpha interferons. In the future new therapies will come into use such as monoclonal antibodies and perhaps also agents blocking different growth factors.

Gastric endocrine cell behavior in Zollinger-Ellison patients upon long-term potent antisecretory treatment

Serum gastrin and gastric endocrine cell numerical densities were examined in 22 patients with long-standing Zollinger-Ellison syndrome who were receiving either ranitidine, omeprazole, or other antisecretory drugs (SMS 201-995 or pirenzepine with or without ranitidine) for long periods of time. Fifteen patients had iterative biopsies. Twenty-one subjects with normal endoscopy, serum gastrin, and acid secretion served as controls. Individual fundic argyrophil cell density was above the highest control value in 77% of the patients, whatever the treatment. Argyrophil cell densities tended to be higher in women than in men. During the survey, fundic carcinoids developed in one ranitidine- and in one omeprazole-treated patient. Fundic argyrophil cell densities were correlated with serum gastrin levels (r' = 0.730, p less than 0.001). Antral somatostatin cell density was not modified in any patients as compared with controls, nor was antral gastrin cell density except in omeprazole-treated patients. In these patients, gastrin cell density and gastrin to somatostatin cell ratio were significantly higher than in all other patients or controls. Such increases may indicate true gastrin cell hyperplasia in relation to drug-induced profound acid inhibition.

Mucosal argyrophil endocrine cells in pernicious anaemia and upper gastrointestinal carcinoid tumours

The number and density of argyrophil endocrine cells were morphometrically calculated in gastric fundal mucosal biopsy specimens taken from 64 patients with pernicious anaemia (five with gastric carcinoids, 15 with nodular argyrophil cell hyperplasia, 44 with diffuse argyrophil cell hyperplasia) and from 14 healthy controls. Similar calculations were also made on the ileal mucosa away from the tumour of 10 patients with ileal carcinoids and 10 controls. In the stomach, the argyrophil cell counts were twice as high in the patients with pernicious anaemia than in controls and the densities in the whole mucosa or in the epithelial structures were similarly three to five times higher. The cell counts in the patients showed positive correlation with the serum gastrin concentration. The patients with nodular argyrophil cell hyperplasia and gastric carcinoids formed a uniform group with the highest cell counts and serum gastrin concentrations; the difference between the groups was in the longer duration of pernicious anaemia in the patients with carcinoid tumours. On the other hand, no endocrine cell hyperplasia was seen in those with ileal carcinoids. It is concluded that fundal mucosal endocrine cells show an increase in patients with pernicious anaemia that is related to the gastrin concentration. This phenomenon may favour the development of hyperplastic endocrine cell nodules and, eventually, carcinoid tumours.

Multiple carcinoids and endocrine cell micronests in type A gastritis. Their morphology, histogenesis, and natural history

Six cases of type A gastritis associated with multiple carcinoids and/or endocrine cell micronests (ECM) in the atrophic fundic mucosa were examined light microscopically, immunohistochemically, and ultrastructurally. The ECM and carcinoids were mainly composed of enterochromaffin-like (ECL) cells. The cells were hyperplastic only in the atrophic fundic glands and pseudopyloric glands, but not in the intestinal metaplastic gland. It is suggested that the development of both the ECM and the carcinoids is highly related to the atrophic change of the fundic mucosa and a trophic action of subsequently raised serum gastrin in type A gastritis and that the both lesions arise from the pseudopyloric glands or atrophic fundic glands. In addition, the definition of neoplastic ECM (microcarcinoid) of the stomach was made with comparative study on both the cases with ECM and multiple carcinoids and the cases with ECM alone.

Enterochromaffin-like cell populations in human fundic mucosa: quantitative studies of their variations with age, sex, and plasma gastrin levels

The human gastric fundal mucosa contains a variety of endocrine cells, the most numerous of which are the so-called enterochromaffin-like (ECL) cells. We have studied the variations with age and sex of the ECL cell populations, utilizing an assessment based on multiple endoscopic biopsies from four groups of subjects. Plasma gastrin levels were also determined in these subjects. In males, endocrine cell densities declined with age but the ECL cell numbers in females opposed this trend. ECL cell counts showed no appreciable differences between young and old females. In older females, there was a high rate of gastritis and increased levels of circulating gastrin. Concentrations in older females (29.6 +/- 8.7 pmol/l) were higher than in both younger (less than 45 years) males (5.3 +/- 1.1 pmol/l) and older (greater than 55 years) males (6.3 +/- 0.6 pmol/l) (P less than 0.05). The plasma gastrin level was also higher in older females than in young females (13.1 +/- 4.5 pmol/l), although this difference failed to reach statistical significance. In conclusion, clinically silent gastritis, raised gastrin levels, and maintenance or rise of ECL cells numbers, in opposition to a general decrease in endocrine cells with age, appear to be features of women of more than 55 years of age. The variations in ECL cell populations reported here should be taken into account when evaluating possible pathological alterations of the stomach.

Omeprazole in the long-term management of patients with acid-related diseases resistant to ranitidine

A total of 143 patients with peptic ulceration of the duodenum, stomach or oesophagus, who did not respond to 3 or more months high-dose treatment with ranitidine (450 mg or more daily), were admitted to oral treatment with omeprazole, 40 mg/day. In 94.4% of the patients, ulcers healed within 2-6 weeks. After healing of their ulcers, 122 patients were admitted to long-term maintenance treatment with omeprazole, 40 mg/day; 91 patients have been on the drug for 1-5.5 years. During maintenance therapy with omeprazole, 40 mg/day, no relapses (verified by endoscopy) have yet occurred and no drug related adverse effects have been observed. There were no significant changes in routine laboratory tests in any patients, including 27 with concomitant liver cirrhosis. Serum gastrin levels were already elevated approximately 2-fold during the initial high-dose ranitidine treatment and rose a further 2-fold at 2-3 months of omeprazole treatment. Thereafter, no further increase of serum gastrin was observed even after 5.5 years of continuous observation. Volume density of G and D cells in the antral mucosa did not change significantly. The volume density of argyrophilic cells in the oxyntic mucosa was 0.73 +/- 0.1% before the start of omeprazole treatment and 0.85 +/- 0.09% after 17-24 months of continuous treatment with omeprazole (ns). In antrectomized patients the volume density was lower (0.23 +/- 0.04%). No clusters of argyrophilic cells were observed in any of the groups. In a control group of patients with gastrinoma the volume density of these cells was higher (1.3 +/- 0.23%, n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Qualitative studies of gastric endocrine cells in patients treated long-term with omeprazole

A total of 543 endoscopic biopsies (a mean of three tissue samples each) were taken from the gastric oxyntic mucosa of 122 patients suffering from reflux oesophagitis or peptic ulcer resistant to H2-receptor antagonist therapy. All were treated with omeprazole, 40 mg/day, until healing and then assigned to 20 mg/day for a mean of 13 months. Proliferative changes of endocrine cells were evaluated according to an internationally agreed classification and the paraffin sections were stained with haematoxylin-eosin and Sevier-Munger silver. Only hyperplastic (no dysplastic or neoplastic) lesions of endocrine cells were observed in 11-19% of patients examined, the incidence and severity of these lesions being unaffected by treatment. A relationship between linear and/or micronodular hyperplasia and chronic gastritis was observed.

Quantitative studies of gastric endocrine cells in patients receiving long-term treatment with omeprazole

A total of 36 patients with chronic gastric or oesophageal peptic ulceration (including 6 with antrectomy), resistant to high-dose ranitidine treatment for at least 3 months, were successfully treated with omeprazole 20-60 mg/day, for periods up to 3 years. Fasting serum gastrin levels were monitored at regular intervals during therapy and multiple gastric mucosal biopsies were taken during gastroscopy every 3-6 months. Gastrin levels increased significantly during the first 6 months of therapy from a mean of 81.5 to 206 pg/ml; a slight decrease was observed thereafter. There was no significant increase in the volume density of argyrophilic cells in the oxyntic mucosa. No clusters of endocrine cells were found in the oxyntic mucosa and no change of G-cell volume density occurred in the antral mucosa under therapy. Omeprazole therapy did not result in any changes in gastrin levels or oxyntic argyrophilic cells in the antrectomized patients. It is concluded that the moderate hypergastrinaemia observed during long-term omeprazole treatment in man does not induce hyperplasia of argyrophilic cells in the oxyntic mucosa.

Effect of 'weekend therapy' with omeprazole on basal and stimulated acid secretion and fasting plasma gastrin in duodenal ulcer patients

The effect of intermittent dosage with omeprazole on basal and pentagastrin stimulated gastric acid secretion and fasting plasma gastrin was assessed in eight duodenal ulcer subjects who were in remission. Omeprazole (20 mg daily) was given for a three day 'weekend' each week for two months. Twenty four hours after the first and eighth weekend, basal and peak acid output were still markedly suppressed (greater than 50%) compared with pretreatment. After the treatment free four days, however (just before the eighth weekend), peak acid output had returned to pretreatment values; basal acid output was still somewhat reduced (mean 3.6 mmol/l) but the difference from baseline was not statistically significant. Fasting plasma gastrin concentration increased slightly but significantly, from a baseline median of 17 pmol/l to 25 and 31 pmol/l respectively, 24 hours after the first and eighth weekends. All but two values (of 16) remained within the reference range. Before the fourth and eighth weekends, and again at 12 days and three months after treatment, gastrin values were not significantly different from baseline. Thus a 'weekend therapy' regimen with this long acting antisecretory compound produces substantial acid suppression, but for only part of the week, with modest and reversible changes in fasting plasma gastrin. It should therefore be suitable for efficacy testing for prevention of recurrence of peptic ulcer or reflux oesophagitis.

Review: the enterochromaffin-like cell, intragastric acidity and the trophic effect of plasma gastrin

Although enterochromaffin-like (ECL) cells form the major endocrine cell population of the non-antral stomach, they have been largely overlooked in the study of gastric disease. In the human, their product and functions are unknown, but they are associated with histamine secretion in rodents. The cells are controlled by neural and hormonal factors, the most significant of the latter being gastrin. Interest in ECL cells has been stimulated by the observation that hyperplasia of these cells, sometimes leading to formation of gastric carcinoid tumours, occurs in conditions of persistent hypergastrinaemia - for example, in response to the achlorhydria of individuals with pernicious anaemia. The advent of new highly potent inhibitors of gastric acid secretion is allowing more information to be obtained on the physiology and functions of the ECL cell. However, there is clearly a great deal more to be discovered about this enigmatic endocrine cell type.

Action of somatostatin analogue (SMS 201-995) on the growth-promoting effect resulting from sustained achlorhydria in rat gastric mucosa, with special reference to endocrine cell behaviour

We investigated whether a new long-acting somatostatin analogue (SMS 201-995) could antagonize the trophic effect induced by hypergastrinaemia, resulting from chronic omeprazole treatment, on the rat gastric mucosa and particularly on endocrine cell growth. SMS was administered concomitantly with omeprazole for 70 days. Gastric morphometric and cell proliferative parameters, gastric acid secretion and plasma gastrin levels were examined. New findings with omeprazole pointed out: (i) a trophic effect on the antral mucosa and (ii) that the increase observed in gastrin cell number was not due to stimulation of gastrin cell production by omeprazole but more likely to a prolongation of the gastrin cells' life span. As compared to omeprazole alone, simultaneous SMS administration significantly decreased the parietal cell (P less than 0.05) and gastrin cell (P less than 0.01) labelling indices, mucosal height of total glandular stomach (P less than 0.05) and antral mucosal height (P less than 0.05). It tended to lower fundic mucosal height and fundic argyrophil cell density (P less than 0.2 and P less than 0.1, respectively). SMS, in our conditions, did not accentuate the inhibitory effect of omeprazole on gastric acid secretion nor reduce high plasma gastrin levels. We conclude that SMS modestly counteracts the growth-promoting effect observed in rat gastric mucosa after prolonged omeprazole treatment.

Diagnosis and treatment of Zollinger-Ellison syndrome

A diagnostic and therapeutic strategy for the management of patients with Zollinger-Ellison syndrome has been developed, based on the review of a large personal experience and the most recent literature. The mainstay of a modern ZES management is the eradication of tumoral processes whenever feasible. Diagnosis is centred upon gastric acid and gastrin secretion measurements both in basal conditions and on secretin stimulation. Recognition of other endocrine involvement and familial inheritance is of the utmost importance in distinguishing sporadic ZES patients from those who have the condition known as multiple endocrine neoplasia type I. Blood calcium and phosphorus levels, parathyroid hormone concentration, combined if necessary with urinary cyclic AMP excretion measurement, should be performed routinely once ZES diagnosis is established or highly suspected. Localization of the tumour is the next essential step, and this has been considerably facilitated by the recent development in imaging techniques: it involves computerized axial tomography and selective abdominal angiography, a combination of which allows tumour detection in 60-70% of sporadic gastrinoma patients, with a maximal sensitivity for well-developed hepatic metastases. In sporadic ZES exploratory laparotomy is legitimate when preoperative localization of the tumour has failed; this laparotomy will allow further detection and then eradication of gastrinomas in a significant number of patients. Control of gastric acid secretion is mandatory throughout the work-up period; modern antisecretory agents are efficacious in most cases; total gastrectomy, when control of acid hypersecretion has failed, is now exceptional. Eradication of the tumour should be attempted in cases of sporadic ZES in the absence of recognizable liver involvement. The chance of a definite cure provided by surgery when performed by an experienced surgeon varies from 20% to 60% in pancreatic and ectopic gastrinomas respectively. In ZES patients with MEN I, exploratory laparotomy is seldom indicated (other than for symptomatic associated endocrine secretion), as the chance of a definite cure by surgery is very rare. Parathyroid surgery is often indicated and should take place before any form of abdominal surgery. In cases of hepatic metastases, chemotherapy with streptozocin and fluorouracil is indicated and soon, perhaps, chemo-embolization.

The effects of famotidine, 40 mg at night, on 24-hour intragastric acidity and plasma gastrin concentration in healthy subjects

The effects of 40 mg oral famotidine at 2115 h on 24-h intragastric acidity and plasma gastrin concentration were measured in a double-blind placebo-controlled study in 10 healthy subjects. The subjects were studied on the 7th day of treatment with either famotidine or placebo. Famotidine, 40 mg at night, caused a pulse of decreased intragastric acidity during the night, with a longer-lasting elevation of plasma gastrin concentration. However, in the latter part of the day there was complete recovery from the antisecretory effects of the drug, with normal intragastric acidity and normal concentrations of plasma gastrin.

Gastric enterochromaffin-like cell hyperplasia and neoplasia in the rat: an indirect effect of the histamine H2-receptor antagonist, BL-6341

Oral administration of BL-6341 hydrochloride, a long-acting histamine H2-receptor antagonist, to rats for 2 years at doses of 10, 55 or 300 mg/kg/day resulted in several changes in the fundic (oxyntic) mucosa of the glandular stomach. The most significant alteration was a proliferation of argyrophil endocrine cells that was demonstrated to be enterochromaffin-like (ECL) cells. The ECL cell proliferation consisted of a continuum of changes involving diffuse hyperplasia, focal adenomatous hyperplasia, and carcinoid tumor formation at the highest dose level of 300 mg/kg. At 55 mg/kg only ECL cell hyperplasia occurred, and at the low dose of 10 mg/kg there were no remarkable proliferative changes. The reference compound, cimetidine (950 mg/kg), produced a degree of ECL cell proliferation that was slightly less, but not significantly different than, that observed with 55 mg/kg of BL-6341. Dose-related elevations of serum gastrin were observed with BL-6341, while cimetidine produced hypergastrinemia that was generally intermediate between that produced by the middle and low doses of BL-6341. The hypergastrinemia resulted from the pharmacologic inhibition of acid secretion, which is the negative feedback mechanism controlling the production of gastrin. Only the 300 mg/kg dose of BL-6341 produced a significant, sustained (24 hours) hypergastrinemia and carcinoid tumors. The chronic, sustained hypergastrinemia was considered to be the primary cause of the ECL cell carcinoid neoplasia. All genetic toxicology tests performed with BL-6341 were negative. It was concluded that the demonstrated hypergastrinemia represents an indirect, hormonal, epigenetic mechanism of tumorigenesis.

A case of multiple carcinoid tumors of the rectum with extraglandular endocrine cell proliferation

A case of multiple carcinoid tumors of the rectum with numerous proliferations of extraglandular endocrine cells is reported. The patient was 52-year-old man with five polypoid lesions in the rectum. The resected rectum contained five macroscopic carcinoid tumors, 36 microcarcinoids, and innumerous extraglandular endocrine cell proliferations. Endocrine cell microproliferations, in their early stage consisting of one to 15 micronests, were mainly located within the bundles of muscularis mucosae, having no contact with mucosal glandular structures. All of the immunohistochemically examined proliferations of extraglandular endocrine cells contained S-100 protein-positive dendritic cells, and some endocrine cells coexisted with submucosal ganglion cells. In contrast, there was no increase in intraglandular endocrine cells. The origin of rectal carcinoid tumor may be the extraglandular endocrine cells, a distinct compartment of mucosal endocrine cells of the rectum.

Multiple carcinoid tumor combined with mucosal carcinoma in the stomach. A case report

A case of gastric multiple carcinoid tumor combined with mucosal carcinoma in a 63-year-old female is reported. The carcinoid tumors, larger than 0.5 mm in diameter, and endocrine cell micronests, smaller than 0.5 mm in diameter, were mostly located in areas of chronic atrophic gastritis. Their distribution was coincident with that of multiple carcinoid tumor in type A gastritis. The majority of the tumor cells were positive for human chorionic gonadotropin (HCG) and Leu 7 by immunohistochemistry and contained various numbers of intracytoplasmic secretory granules as revealed by electron microscopy. Two mucosal carcinoma foci did not show endocrine characteristics. These carcinoid tumors were thought to have originated in HCG-producing argyrophil cells which had been stimulated by hypergastrinemia accompanying chronic atrophic gastritis. The mucosal carcinomas were regarded as incidental.

Gastric carcinoid tumors, endocrine cell hyperplasia, and associated intestinal metaplasia. Histologic, histochemical, and immunohistochemical findings

Eleven cases of gastric carcinoid tumor have been studied to review their clinical and pathologic spectrum, to identify any relationship to pernicious anemia, and to evaluate the accompanying gastric mucosal changes, with particular reference to the endocrine cell population. Seven patients were male and four female; ages ranged from 26 to 83 years. Two male patients had documented pernicious anemia and one female patient had unconfirmed pernicious anemia. All patients had marked gastric intestinal metaplasia (atrophic gastritis), which was predominantly fundal (Type A) in three patients with suspected/proven pernicious anemia and antral (Type B) in the other eight. In seven patients, the tumors were typical carcinoids, whereas in 4 patients the carcinoids were "atypical"; one carcinoid was completely polypoid. All cases were argyrophilic, and focal mucin positivity was present in four. Focal somatostatin immunoreactivity was present in four cases, serotonin in three cases, vasoactive intestinal polypeptide (VIP) in two cases, and gastrin (G) in one case. Endocrine cell hyperplasia was identified in the gastric mucosa of eight of 11 patients, including all cases with pernicious anemia; in three of eight cases, G-cell hyperplasia was evident. Numbers of serotonin-positive cells were increased in areas of intestinal metaplasia in all cases. In two patients, there was marked endocrine-cell hyperplasia with multiple small carcinoid tumorlets; the tumorlets stained for G in one. Gastric intestinal metaplasia includes intestinal-like endocrine cells. An association exists between atrophic gastritis and gastric carcinoids, and there is a histogenetic link between atrophic gastritis and some cases of gastric carcinoid tumor.

Twenty-four-hour intragastric acidity and plasma gastrin concentration in healthy subjects and patients with duodenal or gastric ulcer, or pernicious anaemia

Twenty-four-hour intragastric acidity and plasma gastrin concentration were measured in healthy subjects (n = 16), and patients with duodenal (n = 12) or gastric (n = 10) ulceration, or pernicious anaemia (n = 8). Median integrated 24-hour intragastric acidity was highest in duodenal ulcer patients and lowest in pernicious anaemia patients (1148 and 0 mmol.hour litre-1, respectively). Median integrated 24-hour plasma gastrin was highest in pernicious anaemia and lowest in the healthy subjects (9886 and 238 pmol.hour litre-1, respectively). Pernicious anaemia patients have unremitting hypergastrinaemia throughout the 24 hours. The results of this study not only provide a reference range of acidity and plasma gastrin in health and disease, but also will act as a baseline for future studies using antisecretory drugs.

Twenty-four-hour intragastric acidity and plasma gastrin concentration before and during treatment with either ranitidine or omeprazole

Simultaneous 24-hour intragastric acidity and plasma gastrin concentrations were measured in 12 duodenal ulcer patients before and on the twenty-eighth day of treatment with either ranitidine 150 mg b.d. or omeprazole 20 mg o.m. Median integrated 24-hour intragastric acidity was decreased significantly from 1148 to 490 and 36 mmol.hour litre-1 during treatment with ranitidine and omeprazole, respectively, whilst median intragastric 24-hour plasma gastrin was raised significantly from 328 to 799 and 1519 pmol.hour litre-1 respectively. When the results of all 48 experiments were considered together, there was a significant inverse correlation between the 24-hour integrated values for intragastric acidity and plasma gastrin concentration. Both drugs caused a significant elevation of plasma gastrin throughout the 24 hours, although ranitidine had no effect on intragastric acidity from 1900 to 2200 hours. When compared with similar profiles of acidity and gastrin in pernicious-anaemia patients, the modest elevations of plasma gastrin observed in this study suggest that neither drug will be associated with clinically relevant enterochromaffin-like cell proliferation in duodenal ulcer patients.

Development of gastric argyrophil carcinoid tumors in a case of Zollinger-Ellison syndrome with primary hyperparathyroidism during long-term antisecretory treatment

Fundic argyrophil carcinoid tumors developed in the course of a 5-year continuous treatment with high dosages of H2-antagonists in a well-documented case of Zollinger-Ellison syndrome with primary hyperparathyroidism, high basal acid output, and serum gastrin. Approximately 100 small polyps were disseminated throughout the gastric fundus exclusively, leading to total gastrectomy. Metastatic carcinoid in a lymph node and pancreatic gastrinomas also were found at surgery. Gastric endocrine cell proliferation varied from simple argyrophil cell hyperplasia to carcinoid tumors eroding the surface and infiltrating the submucosa. Ultrastructural studies showed that the tumoral proliferation was heterogeneous, and included tumors composed of enterochromaffin (EC) and typical enterochromaffin-like (EC-L) cells, and tumors in which a majority of cells exhibited dense round granules resembling those of A-like or D1/P endocrine cell types. The risk of developing gastric fundic carcinoid tumors in ZES patients submitted to long-term antisecretory treatment should be given increased attention.

Gastric neuroendocrine cell hyperplasia after treatment with the long-acting, potent H2-receptor antagonist SK&F 93479

The time course and dose response of the neuroendocrine cell hyperplasia in the oxyntic mucosa of the rat was examined after treatment with the potent, long-acting H2-receptor antagonist SK&F 93479 at doses of 0 and 1000 mg/kg orally for 1, 3, 7, and 14 days and at doses of 0, 40, 200, and 1000 mg/kg orally for 1 and 6 months. The number of oxyntic neuroendocrine cells (chromogranin-positive) increased after 7 days of treatment. In the 1- and 6-month studies with doses of 1000 mg/kg, the grading for the number of oxyntic chromogranin-positive cells was 2.5 to 3 times the control levels, and they were distributed mostly throughout the mucosa, whereas at lower doses, which did not produce carcinoid tumours at 2 years, the neuroendocrine cells were distributed in the lower half of the mucosa with 1.5- to 2-fold increases in grades for cell numbers. Increases in cell numbers and cell distribution may be useful factors in the evaluation of the neuroendocrine cell hyperplasia found in, for example, the Zollinger-Ellison syndrome and chronic atrophic gastritis, in which hypergastrinaemia and fundic neuroendocrine cell hyperplasia are present.

Carcinoid tumour of stomach and primary hyperparathyroidism: a new association

Three cases of carcinoid tumour of the stomach associated with primary hyperparathyroidism had the clinical and pathological features of a pluriglandular syndrome. Two of the patients showed multiple small polypoid carcinoids in the non-antral stomach, in conjunction with a parathyroid adenoma in one and parathyroid hyperplasia in the other case. One of these patients was also suffering from pernicious anaemia. A third patient had a large metastasising carcinoid arising in the gastric body and a parathyroid adenoma. Immunohistochemical stains for PGP 9.5 were positive in the carcinoids of all three cases. In all cases the carcinoids showed immunoreactivity for gastrin. A positive family history of endocrine hyperplasia and neoplasia was established in one case. It is suggested that patients with gastrointestinal carcinoids and their families should be evaluated for hyperparathyroidism, and patients with hyperparathyroidism presenting with upper gastrointestinal symptoms should undergo endoscopy to rule out gastric carcinoid tumours.

Review: antisecretory drugs: cellular mechanisms of action

Parietal cell secretory function may be inhibited by three mechanisms. (1) Receptors for gastrin, histamine and acetylcholine are present on the canine parietal cell, and parietal cell function may be directly inhibited by specific antagonists for each of these receptors. (2) Receptor activation of parietal cell function is mediated by cyclic AMP-dependent (histamine) and calcium-dependent (cholinergic agents and gastrin) mechanisms. The antisecretory action of prostaglandins reflect interference with histamine activation of adenylate cyclase. The current generations of calcium channel blockers have only weak antisecretory actions in vivo and are unlikely to be useful in clinical practice. (3) A third mechanism of inhibition is blockade of H+/K(+)-ATPase by substituted benzimidazoles, such as omeprazole. Each of these three mechanism provides modalities of potential clinical usefulness for treating acid-peptic disease. Gastrin and acetylcholine receptors are present on other fundic cells, in addition to the parietal cell. These other cells include the somatostatin cell in the dog fundic mucosa and the histamine-containing enterochromaffin-like (ECL) cell present in the fundic mucosa of several species. The relative impact of these receptors on different cell types on the regulation of acid secretion remains uncertain, and is probably variable among different species. One gastrin receptor of considerable importance is the gastrin receptor that exerts a trophic effect on the ECL cell in the fundic mucosa. Sustained hypergastrinaemia in response to profound hypochlorhydria is associated with hyperplasia of this cell type; the elucidation of the conditions that promote this hyperplasia and the clinical consequences of this association are pressing challenges.

Omeprazole in peptic ulcers resistant to histamine H2-receptor antagonists

Eighteen patients with duodenal, gastric or jejunal ulcers, resistant to at least 3 months treatment with histamine H2-receptor antagonists, singly or in combination with other anti-ulcer drugs, were treated with 40 mg omeprazole once daily for up to 8 weeks. All ulcers healed, the majority within two weeks. After ulcer healing patients were given maintenance therapy with high doses of cimetidine or ranitidine. Of 15 patients on maintenance therapy with H2-receptor antagonists, 12 (80%) developed a relapse after a period ranging from 3 to 52 weeks. Two patients were lost to follow-up. After re-healing on 40 mg omeprazole, two patients were given 20 mg omeprazole daily as maintenance therapy but relapses occurred again after 14 and 26 weeks respectively. After re-healing on 40 mg omeprazole, these two patients and one additional patient received maintenance therapy with 40 mg omeprazole daily. At present these three patients have been relapse-free for periods varying from 16 to 52 weeks. No side effects were registered during treatment with omeprazole. It is therefore concluded that omeprazole is highly effective in healing refractory peptic ulcers and that omeprazole maintenance therapy may be useful for prevention of relapse. Patients are sometimes seen with peptic ulceration which appears resistant to therapy with histamine H2-receptor antagonists, colloidal bismuth subcitrate, sucralfate or pirenzepine, either given as monotherapy for a prolonged period of time or as combination therapy. Usually the reason for such therapeutic failure remains obscure. Whether virtually total abolition of acid secretion will allow ulcer healing in these circumstances is unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a single oral dose of enprostil on gastric secretion and gastrin release. Studies in healthy volunteers and patients with pernicious anemia

In healthy human volunteers, a single oral dose of enprostil (35 micrograms) inhibited basal gastric acid output by a mean of 71 percent, pentagastrin-stimulated output by 46 percent, sham-meal-stimulated output by 48 percent, and histamine-stimulated output by 16 percent. In each case, there was a reduction in both the volume and acidity of the gastric juice. Pepsin output was unchanged. Although enprostil increased the gastric pH, it did not induce basal or post-prandial hypergastrinemia. In patients with hypergastrinemia secondary to achlorhydria, enprostil lowered the basal gastrin level and reduced or abolished the post-prandial gastrin rise in a dose-related fashion. Enprostil reduces basal and stimulated gastric acid secretion and inhibits gastrin release.

Effectiveness of omeprazole in seven patients with Zollinger-Ellison syndrome resistant to histamine H2-receptor antagonists

The inhibitory effect of omeprazole, a benzimidazole derivative, on gastric acid secretion was investigated in seven patients with Zollinger-Ellison syndrome resistant to treatment with large doses of histamine H2-receptor antagonists administered alone or in combination with pirenzepine. In two patients with an acute form of the syndrome, rapid control of acid overproduction was achieved with 180-mg intravenous and 120-mg oral daily doses, respectively. The other five patients, who were free of complication, initially received a standard regimen of omeprazole 60 mg orally once a day; dosage was subsequently adjusted until the basal acid output, measured 1 hr before the next dose of the drug, was less than 10 mmol/hr. The initial daily dose proved to be adequate in three patients and had to be increased to 80 mg and 60 mg bid, respectively in the remaining two patients. In all patients omeprazole therapy resulted in clinical recovery and rapid healing of mucosal lesions. The seven patients have now been followed up for 4-24 months (average 15 months). The adequacy of the daily dosage was periodically reassessed by measuring basal acid output in the hour preceding the morning dose. In one patient initially treated with 180 mg/day, dosage could be reduced to 60 mg/day. In three others, who were initially controlled with 60 mg/day, dosage had to be increased during follow-up. Despite adequate control of gastric acid secretion, one patient underwent total gastrectomy and tumor resection and another died of extensive liver metastases. The five patients still receiving omeprazole remain free of symptoms and mucosal lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Pernicious anaemia and mucosal endocrine cell proliferation of the non-antral stomach

There is a recognised association between pernicious anaemia and the development of gastric carcinoma, endocrine cell hyperplasia, and carcinoid tumour. Multiple endoscopic biopsies from the body mucosa of seven patients with pernicious anaemia showed small intestinal metaplasia with varying degrees of inflammation, fibrosis, and expansion of the lamina propria. Using conventional silver and lead stains, endocrine cells were inconspicuous. Staining for the general neural and neuroendocrine markers NSE and PGP 9.5 revealed a proliferation of endocrine cells in the epithelium and isolated clumps of endocrine cells in the lamina propria. The clumps were composed of two cell types, either small or large. Some of these endocrine cells showed gastrin, 5HT, VIP and substance P immunoreactivity of varying intensity. Ultrastructurally nine morphologically distinct types of granules were found some of which correlated with the immunohistochemistry. Some separate islands were composed solely of endocrine cells while others had a definite neural component, suggesting that the former arise from 'budding off' of enteroendocrine cells and the latter originate from the neuroendocrine cells of the lamina propria plexus. Thus there may be a dual origin of carcinoid tumours. Carcinoid tumours associated with pernicious anaemia tend to be multifocal and are infrequent. Less than 50 such cases have hitherto been reported. Our findings of endocrine cells proliferations in seven cases of pernicious anaemia indicate that this may be an adaptive change that occurs frequently and provides the basis on which carcinoids, less frequently, develop.

[Biermer's disease and selective IgA deficiency. Apropos of a case]

The authors report a case of pernicious anaemia in a 41-year old white man; this case has particular features: rise in mean corpuscular volume, neurological manifestation 8 and 2 years respectively before diagnosis, association with selective IgA deficiency. Relations between pernicious anaemia and immunoglobulin deficiency are discussed.

Subepithelial neuroendocrine cells and carcinoid tumours of the human small intestine and appendix. A comparative immunohistochemical study with regard to serotonin, neuron-specific enolase and S-100 protein reactivity

A comparative immunocytochemical study was performed of subepithelial neuroendocrine cells of the human small intestine and appendix and carcinoid tumours of these sites, using a monoclonal antibody to serotonin and polyclonal antisera against neuron-specific enolase (NSE) and S-100 protein. Subepithelial neuroendocrine cells were easily identified in the lamina propria of the appendix. These cells, which sometimes occurred in aggregates, displayed serotonin and NSE immunoreactivity and were surrounded by S-100 protein immunoreactive cells, presumably of Schwann cell origin. In the appendix scattered cells with corresponding morphological features and immunoreactivity were also observed deep in the submucosa. In addition, subepithelial neuroendocrine cells were sparsely present in the lamina propria of the small intestine, occurring only as single cells in the deeper part of the mucosa below or between the epithelial crypts. Most appendiceal carcinoid tumours (11 of 12 examined cases) were biphasic and consisted of neuroendocrine tumour cells with intermingled S-100 protein immunoreactive cells (Schwann cells) with long cytoplasmic extensions. However, small intestinal (11 cases) and caecal (10 cases) carcinoids lacked S-100 protein immunoreactive cells as an integral component. The results indicate that the appendiceal carcinoids are mostly closely related structurally to the subepithelial neuroendocrine and Schwann cell aggregates of the lamina propria and are thus presumed to be histogenetically related to this cell system, while the histogenesis of small-intestinal and caecal carcinoids remains less clear.

Gastrin and the trophic control of gastric mucosa

Gastrin is a trophic stimulant of the acid producing gastric mucosa. Experiments have been carried out in rats, in which chronic states of either low or high serum gastrin levels were induced by surgical manipulation or drug treatment. A relationship between circulating gastrin and a trophic effect could be demonstrated in the oxyntic mucosa, but not in the pancreas and small intestine. Endocrine cells in the oxyntic mucosa (the ECL cells and A-like cells) are among the target cells for the trophic action of gastrin. The functional significance of these two cell populations is unknown. There is much experimental evidence indicating that they are under functional as well as tropic control of gastrin. The vagus nerve also exerts trophic control on the oxyntic mucosa, including the endocrine cells within it. This could be demonstrated by one-sided truncal vagotomy which caused atrophy of the mucosa and hypoplasia of endocrine cells (notably the ECL cells) on the denervated side of the stomach. Conversely, portacaval shunt greatly increased the number of ECL cells. There was no hypergastrinaemia after portacaval shunt, and no trophic effect on other cell types in the oxyntic mucosa. The factors responsible for the ECL cell proliferation after portacaval shunting remain unknown. Tumours may arise spontaneously from the ECL cells. Such neoplasias have been described in Mastomys (Praomys natalensis) and in man. ECL cell hyperplasia and neoplasia in man, but not in Mastomys, are usually associated with hypergastrinaemia either as a result of a gastrin producing tumour or as a result of achylia (sometimes associated with pernicious anaemia). It is unlikely that gastrin alone is responsible for the neoplasia, though it is quite likely that long-standing hypergastrinaemia triggers or facilitates a sequence of events that ultimately leads to tumour formation, via diffuse ECL cell hyperplasia.

Ultrastructural characterization of fundic endocrine cell hyperplasia associated with atrophic gastritis and hypergastrinaemia

Clinical and experimental evidence indicates that carcinoid tumours of the stomach fundic mucosa represent another example of hormone-dependent neoplasm, gastrin being the hormone involved in tumour induction. In this context hyperplasia of fundic endocrine cells associated with chronic atrophic gastritis (CAG) and hypergastrinaemia is regarded as the most frequent preneoplastic lesion. However, the cell type involved in this hyperplasia has not been clarified. To elucidate this problem fundic endocrine cells were characterized ultrastructurally in 9 patients from which endoscopic gastric biopsies were obtained. ECL cells were the most frequent cell type in 8 cases, in 4 of which they were more numerous than all other cell types taken together. D1 cells were the most frequent type in one case while they were inconspicuous in the other cases. P cells were found with a frequency in each case intermediate between that of ECL cells and that of D1 cells. These results indicate that fundic endocrine cell hyperplasia occurring in hypergastrinaemic CAG is in most cases cytologically similar to that found in other hypergastrinemic conditions, in which the gastrin-dependent ECL cells were already found to prevail. They also explain why fundic carcinoids arising in CAG are mostly composed of ECL cells. The relation between ECL, D1 and P cells, if any, remains obscure.

Does treatment present material risks?

The safety of anti-secretory treatment can only be confirmed by extensive use, although animal studies, human pharmacological investigations, and examination of outcome in controlled trials form essential preliminaries. The interpretation is, however, hindered by the confounding influence of disease present before treatment started, owing to coincident disease. Careful analysis of data is required to demonstrate this phenomenon, which is a major factor impeding the demonstration of drug-induced illness, which mimics ordinary disease. So far a substantial body of data which covers an extensive time after initial drug use has only been collected for cimetidine. This gives reassurance about drug safety during ordinary use, but confirms the difficulty caused by confounding. Studies of other drugs must take the same problems into account during interpretation.

Multifocal gastric carcinoid tumours, achlorhydria, and hypergastrinaemia

Multiple polypoidal carcinoid tumours of the stomach were found in 5 patients with achlorhydria (4 of whom had pernicious anaemia) as a result of autoimmune atrophic gastritis. The tumours were small (nearly all less than 1 cm diameter) and appeared to grow very slowly, if at all; no significant enlargement or complications were seen during periods of observation of up to 6 years. No extragastric hormonal syndromes were identified. They differed from the carcinoid tumours usually found in the intestinal tract by being composed of argyrophil (not argentaffin) cells of the enterochromaffin-like (ECL) type. Fasting plasma levels of gastrin, which is believed to be trophic to ECL cells, were very high in all patients. Thus, chronic hyperplasia of gastric ECL cells (as a result of hypergastrinaemia) may have been responsible for development of the tumours. Long-term, uninterrupted achlorhydria produced by potent inhibitors of gastric acid secretion might therefore predispose to carcinoid tumours of the stomach.

Omeprazole: effective, convenient therapy for Zollinger-Ellison syndrome

The acute and long-term effects of omeprazole on gastric acid secretion were examined in 11 patients with Zollinger-Ellison syndrome. Basal gastric acid secretion was inhibited by 50% 3 h after a single 60-mg dose of omeprazole and 78% 4 h after administration of omeprazole. Patients were treated with a single daily dose of omeprazole, and the dose requirement was defined as the lowest dose of omeprazole that would reduce gastric acid secretion to less than 10 mEq/h during the last hour before the next dose. The mean daily dose requirement was 70 mg (range 20-160 mg). Ten of the 11 patients were given omeprazole once a day and 1 patient required omeprazole every 12 h. When omeprazole was discontinued after several months of therapy, mean basal gastric acid secretion was inhibited by greater than 50% 48 h after administration of omeprazole. Omeprazole continued to inhibit gastric acid secretion during 1-9 mo of therapy and patients remained free of toxicity or side effects related to omeprazole. Omeprazole is a highly effective inhibitor of gastric acid secretion in patients with Zollinger-Ellison syndrome. Because of its potency and long duration of action, omeprazole offers an advance in convenient medical therapy for Zollinger-Ellison syndrome compared with the histamine H2-receptor antagonists.

Gastric endocrine cell hyperplasia and carcinoid tumors in pernicious anemia

Endoscopic screening in 123 patients with pernicious anemia (PA) yielded 4 patients with solitary and 1 patient with multiple gastric carcinoid tumors. Quantitative histologic studies of multiple standardized biopsy specimens showed a significantly increased number of fundic mucosal argyrophil endocrine cells in 40 patients with PA when compared with 15 patients with simple fundic atrophic gastritis (p = 0.002) or 8 normal controls (p = 0.0001). Patients with simple atrophic gastritis had increased numbers of fundic mucosal argyrophil cells as compared with normal controls (p = 0.02). A significant difference was also noticed in the number of antral mucosal argyrophil cells between patients with PA and normal controls (p = 0.01), but not between patients with PA and patients with simple atrophic gastritis. It is concluded that, in addition to having hyperplasia of gastric mucosal argyrophil endocrine cells, patients with PA run an increased risk of developing gastric argyrophil cell carcinoid tumors, which should be regarded as potentially malignant.