Malignant gastric neuroendogrinomas. Ultrastructural and biochemical characterization of their secretory activity

Towards Understanding of Gastric Cancer Based upon Physiological Role of Gastrin and ECL Cells

Simple Summary

Generally, we know that cancers represent genetic changes in tumour cells, but we most often do not know the causes of cancers or how they develop. Our knowledge of the regulation of gastric acid secretion is well known, with the gastric hormone gastrin maintaining gastric acidity by stimulation of the enterochromaffin-like (ECL) cell to release histamine, which subsequently augments acid secretion. Furthermore, it seems to be a general principle that stimulation of function (which, for the ECL cell, is release of histamine) in a parallel way stimulates the proliferation of the same cell. Long-term hyperstimulation of cell division predisposes to genetic changes and, thus, development of tumours. All conditions with reduced gastric acidity result in an increased risk of gastric tumours due to elevated gastrin in order to restore gastric acidity. It is probable that Helicobacter pylori infection (the most important cause of gastric cancer), as well as drugs inhibiting gastric acid secretion induce gastric cancer in the long-term, due to an elevation of gastrin caused by reduced gastric acidity. Gastric carcinomas have been shown to express ECL cell markers, further strengthening this relationship.

Abstract

The stomach is an ideal organ to study because the gastric juice kills most of the swallowed microbes and, thus, creates rather similar milieu among individuals. Combined with a rather easy access to gastric juice, gastric physiology was among the first areas to be studied. During the last century, a rather complete understanding of the regulation of gastric acidity was obtained, establishing the central role of gastrin and the histamine producing enterochromaffin-like (ECL) cell. Similarly, the close connection between regulation of function and proliferation became evident, and, furthermore, that chronic overstimulation of a cell with the ability to proliferate, results in tumour formation. The ECL cell has long been acknowledged to give rise to neuroendocrine tumours (NETs), but not to play any role in carcinogenesis of gastric adenocarcinomas. However, when examining human gastric adenocarcinomas with the best methods presently available (immunohistochemistry with increased sensitivity and in-situ hybridization), it became clear that many of these cancers expressed neuroendocrine markers, suggesting that some of these tumours were of neuroendocrine, and more specifically, ECL cell origin. Thus, the ECL cell and its main regulator, gastrin, are central in human gastric carcinogenesis, which make new possibilities in prevention, prophylaxis, and treatment of this cancer.

Tumor size and depth predict rate of lymph node metastasis and utilization of lymph node sampling in surgically managed gastric carcinoids

BACKGROUND

Radical resection with regional lymphadenectomy is recommended for all sporadic gastric carcinoids. Local resection, however, is accepted for some carcinoids from other gastrointestinal sites (i.e., appendix and rectum). We sought to examine the relation of tumor size and depth to lymph node metastasis to determine whether gastric carcinoids can be selected for endoscopic resection. We also sought to quantify the utilization of lymph node sampling.

METHODS

984 patients with localized gastric carcinoids who underwent cancer-directed surgery between 1983 and 2005 were identified from the Surveillance, Epidemiology, and End Results (SEER) registry database.

RESULTS

Tumor size and depth predicted probability of lymph node metastasis. Lymph node metastasis was not seen in intraepithelial (IE) tumors <2 cm. Of tumors <1 cm invading into the lamina propria or submucosa (LP/SM), 3.4% had lymph node metastasis. Excluding IE tumors <2 cm and LP/SM tumors <1 cm, all other subgroups based on size and depth had rates of lymph node metastasis ≥ 8%. Tumor size and depth predicted probability of lymph node sampling. Overall, only 21% of tumors had lymph node sampling. Excluding IE tumors <2 cm and LP/SM tumors <1 cm, only 43% of tumors had lymph node sampling.

CONCLUSIONS

Tumor size and depth predict lymph node metastasis for gastric carcinoids. Endoscopic resection may be appropriate for intraepithelial (IE) tumors <2 cm and perhaps tumors <1 cm invading into the lamina propria or submucosa. Lymph node sampling is underused for gastric carcinoids at high risk for lymph node metastasis.

Unusual case of small cell gastric carcinoma: case report and literature review

BACKGROUND

Small cell carcinomas are among the most aggressive, poorly differentiated, and highly malignant of the neuroendocrine tumors (NETs). Of which, small cell gastric carcinoma is a rare small cell neuroendocrine tumor. The purpose of our study was to present this case and perform a comprehensive literature review.

METHODS AND RESULTS

We review a case of small cell gastric carcinoma that is particularly unusual in that it occurred in a woman from the US when the majority of cases of small cell gastric carcinoma have been reported in men from East Asia, and more specifically, from Japan. The diagnosis was made after endoscopy revealed a large ulcerated mass in the gastric cardia of Borrmann type 3. Biopsies revealed multiple small basophilic cells underlying the squamous epithelium of the esophagus and cardiac mucosa, indicating the presence of a tumor at the gastroesophageal junction. Immunostaining established the diagnosis with positive stains for chromogranin, synaptophysin, and CD56. Our patient is being treated with chemotherapy, but many different treatment regimens have been tried for small cell gastric carcinoma with variable success.

CONCLUSIONS

Overall prognosis for small cell gastric carcinoma is dismal. Neuroendocrine tumors in general have variable clinical behaviors and prognosis is dependent on the neuroendocrine tumor type. The adoption of a standardized classification system for neuroendocrine tumors could improve the recognition of infrequently encountered neuroendocrine tumors like small cell gastric carcinoma and will enhance strategies for treatment and thus improve prognosis for patients with these rare and aggressive tumors.

A rare case of poorly differentiated endocrine cell carcinoma of the stomach with signet ring cell differentiation

There have been few reports of the dual differentiation of different cell types within the same gastric tumor. Here, we report a rare case of poorly differentiated endocrine cell carcinoma with an associated differentiated signet ring cell population arising in the stomach. The histological appearance of the tumor by light microscopy matched the phenotype of endocrine cell carcinoma and signet ring cell differentiation with mucinous lakes. Cells with a phenotype intermediate between the two differentiated cell types were also seen in the tumor. Both the endocrine cell carcinoma and the signet ring cells were diffusely positive for chromogranin A and synaptophysin, a finding that is consistent with endocrine differentiation by immunohistochemical examination. The patient's postoperative clinical course had a poor prognosis, with aggressive tumor progression. Paraaortic lymph node recurrence was found 6 months after the operation, and the patient died of the primary disease 16 months after the surgical treatment.

Small cell carcinomas of the gastrointestinal tract: clinicopathological features and treatment approach

Small cell undifferentiated carcinoma (SmCC) of the gastrointestinal tract (GIT) is a rare and highly aggressive malignancy. To date, fewer than 1,000 cases have been reported, with an estimated prevalence of 0.1% to 1% of all gastrointestinal (GI) tumors. Data on the disease are scarce due to its rarity and the fact that most authors have focused on one site within the GIT. In light of the limited data and its perceived similarity to SmCC of the lung, the disease has usually been treated as the latter. Nevertheless, recent clinicopathologic and molecular data imply several differences between the two entities, questioning the extent to which extrapolations from one to the other can be made. We review the available data on GI SmCC with emphasis on outlining its clinicopathologic features and the recommended treatment approach.

Gastric large cell neuroendocrine carcinomas: a distinct clinicopathologic entity

The current histologic classifications of gastric cancers define only carcinoids and small cell carcinomas in the neuroendocrine (NE) category. This study aimed to characterize the histologic and clinical features of high-grade gastric NE carcinomas of nonsmall cell type, tentatively named large cell neuroendocrine carcinoma (LCNEC). Tumors with histologic features suspicious of NE differentiation were selected by a histologic review of 2835 resected gastric cancers, and those with a NE phenotype in > 50% and 1% to approximately 50% tumor cells assessed by expressing chromogranin A and/or synaptophysin were defined as LCNEC and adenocarcinoma with neuroendocrine differentiation (ACNED), respectively. One hundred ninety-nine tumors were selected and of the 109 positive for chromogranin A and/or synaptophysin, 42 and 44 met the criteria for LCNEC and ACNED, respectively. Generally, LCNECs demonstrated less predominant NE morphology than carcinoids, and could be roughly divided into solid (30 cases), tubular (7 cases), and scirrhous (5 cases) subtypes with reference to their main growth pattern. The prognosis of LCNECs was significantly worse than that of conventional adenocarcinomas (P < 0.0001). Thus, this study shows that the spectrum of gastric NE tumors is broader than has previously been recognized and LCNEC is not only a distinct histopathologic entity, but also a distinct clinical entity. Furthermore, the prognosis of ACNEDs was also significantly worse than that of adenocarcinomas (P < 0.0001), and some ACNEDs might actually have been LCNECs, and survival analysis showed that > 20% positivity of NE markers could be enough to characterize LCNEC, as long as light microscopic NE morphology was present in the tumor.

Small-cell carcinoma of the gastrointestinal tract: a retrospective study of 64 cases

Small-cell carcinoma (SmCC) of the gastrointestinal tract is a very rare and aggressive malignancy. To better define its clinicopathological features, the records of all patients with this disease seen at Memorial Sloan Kettering Cancer Center between 1980 and 2002 (n=64) were reviewed. The most common primary tumour locations were in the large bowel and oesophagus. Predisposing medical conditions for non-small-cell cancers, positive family cancer history, and metachronous tumours were common. In all, 37% had mixed tumour histology and 48% presented with extensive disease, according to the Veterans' Administration Lung Study group (VALSG) staging system used for small-cell lung cancer. Treatment outcome in limited disease (LD) suggested a role for surgery and chemotherapy. Platinum-based regimens resulted in a 50% response rate. The 2-year survival was 23% and two prognostic factors were identified, the extent of disease according to the VALSG system (P<0.01) and TNM stage (P=0.03). Anatomic location had no clinical impact. In conclusion, SmCC from various gastrointestinal sites can be viewed as one clinical entity. Mixed tumour histology is common and may affect therapy. Surgery, combined with chemotherapy, should be considered for LD. The value of the VALSG system was implied and possible differences from small-cell lung cancer were noted.

Small-Cell Carcinomas of the Gastrointestinal Tract: A Review

Purpose

To improve our understanding of the entity of small-cell carcinoma (SmCC) of the gastrointestinal (GI) tract.

Methods

A MEDLINE search was done, using the terms “small cell carcinoma” or “oat cell carcinoma” combined with “gastrointestinal” or with any of the GI sites, for the period 1970 to 2003. The 138 eligible reports identified in this way were reviewed for clinical data.

Results

To date, approximately 544 cases of GI SmCC have been reported. The disease represents 0.1% to 1% of all GI malignancies, with the esophagus being the most common primary site. A majority of patients present with overt distant metastases. Systemic symptoms are common; ectopic hormonal secretion may occur. By light microscopy, GI SmCCs are essentially indistinguishable from primary pulmonary SmCC. The presence of non-SmCC components is common. Data from molecular analysis of the disease has identified some similarities to pulmonary SmCC. Chemotherapy represents the main treatment option, with modest impact on survival. In locoregional disease, the literature suggests that treatment be initiated using chemoradiotherapy and then, if metastatic disease is still excluded, surgical resection be considered. The disease is highly aggressive, and survival is in the range of several weeks for untreated patients and of 6 to 12 months for those receiving therapy.

Conclusion

SmCC of the GI tract is a rare and lethal disease. Although there are many similarities to pulmonary SmCC, some differences between the two entities are suggested. While chemotherapy can achieve significant palliation, surgery may have a potential impact on long-term survival of patients with locoregional disease.

Clinical and histopathological tumour progression in ECL cell carcinoids ("ECLomas")

AIMS

The aims of this study were to illustrate the malignant potential of gastric enterochromaffin-like (ECL) cell carcinoids (ECLomas) associated with hypergastrinemia, and the gradual neoplastic progression of such tumours. In addition, we examined whether the tyramide signal amplification (TSA) technique could visualize immunohistochemical (IHC) neuroendocrine (NE) features in the dedifferentiated neoplastic ECL cells which were not detected by conventional methods.

METHODS

Conventional histopathological and IHC methods for visualizing ECL cells and cell proliferation were used in addition to the TSA technique.

OBSERVATIONS

Our patient was followed for 5 years. During that period, her ECLoma displayed all the signs of classical tumour progression, ultimately with the appearance of metastases in the regional lymph nodes, the liver and the skin. The neoplastic ECL cells became progressively dedifferentiated with an increasing number of Ki-67 immunoreactive (IR) cell nuclei. In addition, there was a substantial decrease in argyrophil and IR NE cells that could be visualized by conventional methods. By applying the TSA technique, however, the number of IR tumour cells increased considerably.

CONCLUSIONS

ECLomas secondary to hypergastrinemia should be closely followed for signs of clinical and histopathological tumour progression. Such ECLomas deserve early, active, radical surgical treatment. The TSA technique is a valuable tool for visualizing the characteristic IHC features in dedifferentiated NE cells.

Primary advanced gastric small cell carcinoma: a case report and review of the literature

We report a 73-yr-old man with primary advanced gastric small cell carcinoma, pure type. A large, Borrman type I tumor was located from the cardia to the entire gastric fundus and upper body. Atypical cells showed a round nucleus, small nucleolus, dense to granular chromatin, and scant cytoplasm. The histological findings indicates an advanced stage and exposure to the gastric serosa. Mitotic figures were observed. There was a proliferation of a sheet-like, solid pattern, but no rosette-like, sqamoid, or glandular patterns. The neoplastic cells were positive for Leu-7 (CD57) and 123C3 (CD56, neural cell adhesion molecule, NCAM) on the surface membrane. We diagnosed this case as primary advanced gastric small cell carcinoma, pure type, and report that Leu-7 and 123C3 monoclonal antibodies are useful markers for gastric small cell carcinoma. The 32 previously reported cases of gastric small cell carcinoma are also reviewed.

ECL cell tumor and poorly differentiated endocrine carcinoma of the stomach: prognostic evaluation by pathological analysis

BACKGROUND & AIMS

Gastric endocrine tumors show a wide spectrum of clinical behavior, and prognostic assessement of individual tumors is difficult. The aims of this work were to identify predictors of tumor malignancy and patient outcome and to provide a rationale for treatment guidelines.

METHODS

Gastric endocrine tumors (86 enterochromaffin-like cell carcinoids and 16 poorly differentiated carcinomas) were investigated for 15 clinicopathologic variables and for expression of Ki67, P53, and BCL-2 proteins. Data were analyzed by univariate and multivariate statistics for evidence of tumor malignancy and patient survival.

RESULTS

Histological grades 2 and 3, size >/=3 cm, 9 or more mitoses, or >/=300 Ki67-positive cells per 10 high-power fields identified 26 of 33 (79%) malignant (metastatic or deeply invasive) tumors, and size <1 cm and/or growth restricted to the mucosa characterized 46 of 69 (67%) tumors with benign behavior during a median follow-up of 39 months. Malignancy-predictive models were developed using angioinvasion, size, clinicopathologic type, mitotic index, and Ki67 index. The same variables, in addition to deep gastric wall invasion and histological grade, predicted patient outcome.

CONCLUSIONS

Criteria for the assessment of malignancy risk and patient outcome were developed for the different tumors, providing a basis for treatment guidelines.

Gastric small-cell carcinoma in Japan: a case report and review of the literature

The authors encountered a patient with primary gastric small-cell carcinoma (primary gastric SCC). Histologic examination revealed combined carcinoma containing non-small-cell elements such as adenocarcinoma and squamous cell differentiation. On preoperative biopsy, only well-differentiated adenocarcinoma was collected. Since gastric SCC was first reported in 1976, this type of carcinoma has been detected in 54 patients in Japan. Concerning these cases, the authors reviewed the light and/or electron microscopic findings of neuroendocrine granules, positive reaction for neuron-specific enolase staining, and the histologic type of resected specimens. There were only three patients positive for neuron-specific enolase in which light and electron microscopy demonstrated neuroendocrine granules. However, 50 patients (approximately 93%) overall satisfied at least one of these findings. Concerning the histologic characteristics of the resected specimens, multidirectional differentiation was more markedly observed compared with that in SCC of the lung. Adenocarcinomatous and/or squamous differentiation was observed in more than half the cases, and preoperative biopsy suggested carcinoma other than SCC or undifferentiated carcinoma in several cases.

Gastrointestinal endocrine tumours. Pathology

Neuroendocrine tumours can form in any part of the gastrointestinal tract. The most common types are the ECL cell tumours of the oxyntic mucosa of the stomach, G cell tumours of the duodenum, argentaffin, EC cell tumours of the small intestine and L cell tumours of the large bowel. The only well-defined clinical syndromes associated with hormone hypersecretion are ZES, resulting from duodenal gastrinomas, and carcinoid syndrome, caused by malignant argentaffin tumours. Genetic predisposition has been demonstrated for some tumour types, e.g. duodenal gastrinoma in MEN 1 and duodenal somatostatin cell tumours in MEN 2. Other factors predisposing to the genesis of these lesions include circulating hormone levels and the maintenance of chronic inflammatory states. As with most neuroendocrine tumours, malignant potential is difficult to assess on the basis of histology alone and prognostic evaluation depends more on size and evidence of local invasion and/or distant metastases.

Fine-needle aspiration cytology of metastatic small cell carcinoma of the colon: a report of three cases

Small cell carcinoma of the large intestine is a rare, extremely aggressive malignancy often associated with an overlying adenoma. We report three cases of metastatic small cell carcinoma of the colon diagnosed by fine-needle aspiration (FNA) biopsy. Two of the patients were women (ages 33 and 46 yr old) and one was a man (69 yr old). FNA biopsy established the diagnosis of metastatic small cell carcinoma involving the liver (2 cases) and soft tissue of the scapular region (1 case). In one patient, the FNA diagnosis of hepatic metastases preceded identification of the primary site. Subsequently, the patient was found to have a small cell carcinoma subadjacent to a colonic villous adenoma, illustrating the importance of investigating villous lesions of the colon in patients with metastatic small cell carcinoma of unknown primary origin (especially in non-smokers). All three cases showed the characteristic cytologic features of small cell carcinoma. Ancillary studies performed on aspirated material confirmed the diagnosis of small cell carcinoma in one case. Immunocytochemical studies revealed punctate cytokeratin and diffuse neuron-specific enolase (NSE) positivity of the malignant cells. Ultrastructurally neurosecretory granules were evident. To the best of our knowledge, this is the first FNA cytologic report of metastatic small cell carcinoma of the large intestine. This FNA report also demonstrates when a small cell carcinoma is detected in a metastatic site in a patient lacking a lung primary, a likely primary site could be adjacent or beneath a polypoid lesion of the colon.

Gastrointestinal neuroendocrine cell proliferations

The gastrointestinal neuroendocrine cell proliferations are comprised of a few hyperplasias and various neoplasias. The better characterized hyperplasias include G-cell hyperplasia, either primary or secondary, enterochromaffin-like (ECL)-cell hyperplasias, generally secondary to hypergastrinemia, and EC-cell hyperplasias. The neoplasias include carcinoid tumors, demonstrating low malignancy and divided into foregut, midgut, and hindgut varieties, poorly differentiated neuroendocrine carcinomas resembling their pulmonary counterparts the "oat cell" carcinomas both in histological pattern and in their highly malignant behavior mixed endo-exocrine tumors, which in turn can be divided into composite tumors formed by a population of endocrine cells and a population of exocrine cells, and amphicrine tumors formed by a uniform population of cells with a mixture of endocrine and exocrine phenotypic traits. Although some of these mixed tumors show a degree of malignancy intermediate between the classical carcinoid and an adenocarcinoma, more information must be gathered to establish firm prognostic parameters for these relatively new entities.

Three subtypes of gastric argyrophil carcinoid and the gastric neuroendocrine carcinoma: a clinicopathologic study

BACKGROUND

Enterochromaffinlike (ECL) cell carcinoids recently observed in rats stimulated new interest in gastric endocrine tumors arising in humans.

METHODS

Paraffin-embedded sections of 55 endocrine tumor cases were stained with H&E, mucin tests were performed, and immunoperoxidase was used for detecting endocrine markers; 23 cases were also investigated ultrastructurally.

RESULTS

Forty-five argyrophil carcinoids, 9 neuroendocrine carcinomas, and 1 gastrinoma were identified. Three clinicopathologic subtypes of carcinoids were characterized: (1) twenty-eight cases, none metastatic, arose in a background of body-fundus atrophic gastritis and hypergastrinemia; (2) seven cases, 2 locally metastatic, were associated with hypertrophic gastropathy and hypergastrinemia due to multiple endocrine neoplasia/Zollinger-Ellison syndrome; and (3) ten were sporadic cases, 7 of which were deeply invasive, 6 metastatic, and 5 histologically atypical. All carcinoids showed histochemical and ultrastructural patterns of ECL cells. The 9 neuroendocrine carcinomas, all deeply invasive and metastatic, were composed of anaplastic, small- to intermediate-sized cells with high mitotic index and focal necrosis.

CONCLUSIONS

Gastrin-promoted carcinoids represent a benign or low grade tumor disease, whereas sporadic carcinoids and neuroendocrine carcinomas are life-threatening neoplasms, independent of gastrin promotion.

The enterochromaffin-like (ECL) cell. Physiological and pathophysiological role

Histamine has a central role in the regulation of gastric acid secretion. This histamine is produced by and released from the enterochromaffin-like (ECL) cell which accordingly has a key-regulatory role in the oxyntic mucosa. Gastrin and the vagal nerves stimulate the formation and release of histamine from the ECL cell. Moreover, gastrin and the vagal nerves also stimulate the proliferation of the ECL cell. An increased ECL cell density may partly explain the increased acid secretion in patients with duodenal ulcer, particularly in patients with Zollinger-Ellison syndrome. The reduced potency of histamine-2 blockers in patients with Zollinger-Ellison syndrome is probably due to increased histamine release by an elevated ECL cell mass. Prolonged and profound hypergastrinemia may lead to ECLomas. Moreover, a proportion of diffuse gastric carcinomas may originate from ECL cells.

Neuroendocrine carcinoma of the stomach with extensive somatostatin immunoreactivity

Upper gastrointestinal tract neuroendocrine tumors producing predominantly somatostatin have thus far been described only in the duodenum; their characteristic features include the frequent presence of psammoma bodies (psammomatous somatostinomas), and the association with von Recklinghausen's neurofibromatosis. Gastric neuroendocrine tumors, on the other hand, tend to display immunoreactivity to serotonin but may include small subpopulations producing gastrin, motilin, pancreatic polypeptide, and somatostatin. In this report we describe a neuroendocrine carcinoma of the stomach with rapidly fatal outcome, displaying neurosecretory granules by electron microscopy and immunoreactivity to pan-neuroendocrine markers, ie, chromogranin and neuron-specific enolase. The only neuroendocrine regulatory peptide detected in the tumor was somatostatin, identified by immunohistochemistry in the majority of neoplastic cells. In contrast with duodenal somatostinomas, there were no psammoma bodies and no demonstrable association with von Recklinghausen's neurofibromatosis. To our knowledge this appears to be the first report of a malignant neuroendocrine tumor with diffuse somatostatin immunoreactivity.

Ultrastructural and immunocytochemical study of a primary gastrinoma of the liver

A primary hepatic gastrinoma found in a 13-year-old boy was studied by light microscopy, immunohistochemistry, electron microscopy, and immunoelectron microscopy. Results were consistent with a neuroendocrine neoplasm with abundant gastrin-immunoreactive cells. Unlike all previously reported cases of primary hepatic neuroendocrine tumors, which have been endocrinologically asymptomatic, the patient had a Zollinger-Ellison syndrome apparently cured by surgical resection of the tumor.

Gastric small cell carcinoma with squamous and neuroendocrine differentiation

A rare gastric carcinoma containing diverse components, that is, neuroendocrine (small cell carcinoma), squamous and gland-like elements in an 82 yr old woman is described. Radiologic examination revealed a large ulcerated tumor, and a Borrmann type II tumor, 6.5 x 5 cm, was found in the resected stomach. Histologically, the tumor was mainly composed of small cells with hyperchromatic nuclei and scant cytoplasm. Argyrophilic granules were seen in these cells. There were also scattered foci of large cells with features of squamous cells, and many intermediate cells with oncocytic cytoplasm. The small cancer cells were positive for chromogranin A and neuron specific enolase. Squamous cell nests were positive for high molecular cytokeratin (CK), and intermediate cells were positive for low molecular CK. Electron microscopic examination revealed secretory granules in the small cells and tonofilaments in the squamous cells. This tumor might have originated from the pluripotential stem cell in the gastric epithelium.

Extrapulmonary and pulmonary small-cell carcinoma: tumor biology, therapy, and outcome

Extrapulmonary small-cell cancer is a distinct clinicopathological entity from small-cell anaplastic carcinoma of the lung. Approximately 1,000 cases have been projected annually in the United States, which represents an overall incidence of between 0.1% and 0.4% of all cancer. Not surprisingly then, little information is available regarding the treatment of this disease, which presents a challenge to the clinician when it is regionally confined. The majority of patients with extrapulmonary small-cell neoplasms have only been treated with local modalities of therapy, surgery, radiation, or a combination of both. Prolonged survival is not infrequent, which is in contrast to the experience for small-cell lung cancer and surprising given our current systemic approach to patients with this disease. This report will summarize the similarities and differences in biology, natural history, and clinical characteristics of patients with extrapulmonary small-cell cancer and small-cell anaplastic carcinoma of the lung. The histogenesis of small-cell cancer is briefly reviewed. A general therapeutic approach to patients with small-cell lung cancer is reported. Lastly, recommendations for therapy of patients with regionally confined extrapulmonary small-cell cancer by primary site are outlined.

Small cell carcinoma of the pancreas and biliary tract

Four cases of anaplastic carcinoma of the pancreas or biliary tract were studied clinicopathologically and immunohistochemically. All four cases were intermediate cell type and contained a minimum amount of microscopic foci of differentiated glandular adenocarcinoma. Argyrophilic tumor cells were not seen in any of the four tumors. Immunohistochemically, no tumor was positive for hormonal products, but all tumors were positive for epithelial markers. These findings suggest that the anaplastic carcinoma are not derived from argyrophilic cells, but rather from adenocarcinomas which have the potential for anaplastic metaplasia. The long-term survival of one patient emphasized the importance of chemotherapy in the treatment of small cell carcinoma of the pancreas and biliary tract.

Small cell carcinoma of the stomach. Case report and review of the literature

Small cell carcinoma of the stomach is an unusual and rare neoplasm with only eight reported cases in the world literature. Like small cell carcinomas elsewhere, they possess rapid growth ability and high propensity to metastasize with short survival. Clinically, small cell carcinoma is indistinguishable from adenocarcinoma. Because of the rarity of gastric small cell carcinoma, there is minimal information available on the optimal treatment. Herein, we report on a patient with metastatic pure small cell carcinoma of the stomach. He underwent palliative surgery and postoperative combination chemotherapy with transient partial response. He died 10 months after diagnosis with progressive widespread disease.

Diagnostic pathology of gastrointestinal and pancreatic neuroendocrine tumours

The increased knowledge of the pathobiology of gastrointestinal and pancreatic neuroendocrine tumours and the improved therapeutic possibilities have brought a demand for more precise diagnosis. Although the neuroendocrine 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 neuroendocrine tumours of the gastrointestinal tract (carcinoids) and pancreas (insulomas). Midgut carcinoids, which predominate among these tumours almost unexceptionally contain serotonin. This biogenic amine can be demonstrated by the argentaffin reaction of Masson, serotonin immunoreactivity or by formalin-induced fluorescence. The characteristic staining pattern of midgut carcinoids is almost invariably preserved in the metastases and can thus be used to reveal a primary midgut carcinoid. The enterochromaffin-like (ECL) cell carcinoids of the body and fundic area of the stomach are argyrophil with Sevier-Munger silver stain. Other neuroendocrine tumours, viz, antral, duodenal and rectal carcinoids and insulomas, should be studied by a battery of relevant peptide hormone antisera for adequate diagnosis. About 50% of all insulin-producing insulomas are endowed with stromal amyloid deposits, which chemically are composed of a peptide designated islet amyloid polypeptide. This molecule has been observed by electron microscopical immunocytochemistry to occur exclusively in the beta-cells and is co-stored with insulin in the beta-cell granules.

Neuroendocrine tumors of the gastrointestinal tract

Neoplastic proliferations of neuroendocrine cells (NE) may occur throughout the entire GI tract but affect particularly appendix and ileum ("midgut carcinoids"), rectum ("hindgut carcinoids"), as well as stomach and the duodenum ("foregut carcinoids"). Only more exceptionally, they arise in the esophagus, jejunum and colon. The NE tumors encompass a heterogeneous gross and microscopic structural spectrum, ranging from inconspicuous microproliferations ("mucous membrane nevi") to bulky tumor masses. Their growth patterns are usually characteristic and easily recognized. In doubtful cases their NE differentiation becomes established by a characteristic silver affinity, by the ultrastructurally observed presence of characteristic "endocrine" secretion granules, and by immunohistochemically detectable occurrence of "pan-NE markers" (neuron-specific enolase, chromogranins, and synaptophysin), biogenic amines (mainly serotonin), and neurohormonal peptides. Foregut carcinoids usually contain serotonin, gastrin, and somatostatin, midgut carcinoids often only serotonin and tachykinins, whereas the hindgut carcinoids as a rule are multihormonal with a wide spectrum of hormonal peptides, including even insulin. Most GI NE tumors are found in the appendix (50%) and the ileum (30%). Practically all (98%) of the appendiceal NE tumors are benign. They have recently been proposed as arising from apparently Schwann-cell-related NE cells in the submucosa, whereas the ileal--and probably also all the other non-appendiceal NE tumors--are derived from the totipotential cells in epithelial crypts of the mucosa. Among the ileal NE neoplasms a large number can metastasize and result in a fatal outcome. The ability to metastasize is related to the size and to the multiplicity of the primary tumors at the time of initial diagnosis and, to some extent, to their histopathologic growth pattern. Now, some relationship between the prognosis and the cytochemically assessed nuclear DNA content of the NE tumor cells has also been established; not less than about 1/4 to 1/3 seem to be aneuploid. Almost 90% of the rectal carcinoids are benign. Exceptionally, a highly malignant NE neoplasms can arise from the colon/rectum--as well as from the esophagus--composed of NE cells of small and intermediate size. The NE tumors of the stomach are often composed of ECL (enterochromaffin-cell-like) cells; such ECL cell carcinoids are related to atrophic gastritis with pernicious anemia; experimentally, they can be induced by hypergastrinemia in rats. Duodenal carcinoids often contain psammoma bodies and can be associated with neurofibromatosis.

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.

Malignant carcinoid of the pancreas: a cytologic, ultrastructural, and immunocytochemical study of a case diagnosed by fine-needle aspiration of a supraclavicular node metastasis

Carcinoid tumor of the pancreas is extremely rare. This article describes the case of a 22-year-old woman who manifested a typical carcinoid syndrome; a definitive diagnosis of a metastatic carcinoid tumor was made from needle aspiration of a supraclavicular lymph node using morphologic, immunocytochemical, and ultrastructural criteria. The carcinoid tumor was subsequently shown to be of pancreatic origin.

Nuclear DNA recordings in gastric carcinoids. A cytofluorometric study on single tumour cells

Cytofluorometric nuclear DNA analyses were performed on single tumour cells from eight argyrophilic gastric carcinoids. Three tumours displayed grossly diploid DNA values, with a fraction of S-phase cells of 1-8%. Four other tumours were also mainly diploid, but showed an increased number of tetraploid cells, and one tumour was aneuploid with a stem-cell line of triploid cells. These and previous results indicate that gastric carcinoids are relatively heterogenous with respect to their morphology, nuclear DNA profiles and biological behaviour, in contrast to most intestinal "classical" carcinoids. Furthermore, the results are in accordance with the suggestion that gastric carcinoids may represent a highly differentiated variety within a spectrum of neuroendocrine neoplasia analogous to the corresponding variety observed in the bronchus (carcinoid-small cell, undifferentiated carcinoma).

Characterization of four main cell types in gastric cancer: foveolar, mucopeptic, intestinal columnar and goblet cells. An histopathologic, histochemical and ultrastructural study of "early" and "advanced" tumours

Gastrectomy specimens of 148 gastric cancers, 40 of them being intramucosal or microinvasive, 27 penetrating the submucosa and 81 invading the muscularis propria, with or without involvement of the serosa and perigastric tissues, have been investigated with conventional histopathologic techniques, mucin histochemistry and electron microscopy to characterize the various lines of tumour cell differentiation and to correlate these with the histologic patterns of tumour growth. More or less differentiated intestinal columnar, intestinal goblet, gastric foveolar or mucopeptic cells were recognized in most tumours, of glandular, diffuse or mucoid type. Although simultaneous expression of more than one cell type into the same tumour occurred very frequently, intestinal columnar cells were more prominent in tubular adenocarcinomas, goblet cells (especially of colorectal type) in mucoid cancers, mucopeptic cells in diffuse cancers of invasive desmoplastic type and foveolar cells in diffuse cancers of intramucosal signet-ring cell type. In general, an increased tendency to foveolar cell differentiation and a reduced tendency to mucopeptic differentiation has been found in intramucosal cancers as compared to invasive cancers. It is concluded that the type of tumour cell differentiation, which might have some influence on the natural history of gastric cancer, is better related with more defined tumour subtypes than with the usually recognized glandular or diffuse patterns.

Long term survival case of small (oat) cell carcinoma of the rectum

A long term survival case of small (oat) cell carcinoma of the rectum in a 39-year-old female is presented. She complained of anal pain and occasional anal bleeding. The tumor was located at the anterior wall in the lower rectum. Biopsy specimens revealed a carcinoid tumor. She underwent trans-anal local resection for the first time in December, 1980. Macroscopic findings of the resected specimen showed a small nodule, 0.4 by 0.4 by 0.5 cm, with yellowish cut-surface. Microscopically, the tumor deeply invaded the submucosal layer. The appearances were indistinguishable from pulmonary small (oat) cell carcinoma. Since lymphatic permeations were moderately recognized in the tumor, she underwent radical operation (Miles' operation) with lymphadenectomy. Microscopic findings of the resected rectum revealed an intramural metastatic lesion with marked lymphatic permeations in the submucosal layer 2 cm distant from the primary lesion. Up to date, there is no evidence of local recurrence or liver metastasis. Small (oat) cell carcinoma of the rectum easily metastasizes lymphogenously through the lymph system from an early stage of the development. Wide surgical resection will be needed to give a long term survival even if the tumor is extremely small.

A neuroendocrine tumor of the small intestine with a karyotype of 46,XY,t(11;22)

Direct preparations of cells from a neuroendocrine carcinoma of the small intestine reveal a karyotype of 46,XY,t(11;22)(q25;q12). Though only 13 cells could be analyzed from both direct and 24 hour preparations, all revealed the translocation; no normal cell line was seen. The patient had not been treated at the time of biopsy. A similar translocation recently has been reported in a number of cases of Ewing's sarcoma and in peripheral neuroepithelioma. This common occurrence, along with the observation that a rearranged chromosome #22 with breakpoints at q11 or q12 are observed in other neoplasias including leukemia, suggests a possible causative role for these phenomena.

The prevalence, prognostic significance and hormonal content of endocrine cells in gastric cancer

Twenty-six of 100 cases of gastric adenocarcinoma contained argyrophil cells. All these tumours were carcino-embryonic antigen positive and 13 contained variable amounts of gastro-enteropancreatic peptides and amines. There was no significant difference in mucin type, extent or incidence of intestinal metaplasia between tumours with and those without endocrine cells. The prognosis for both groups was similarly poor, contrasting with that for carcinoid and atypical carcinoid. Endocrine cell hyperplasia was evident in the adjacent mucosa in some of the cases of endocrine positive tumours. There was no association between achlorhydria and the presence of endocrine cells in the tumours. The origin of the neoplastic endocrine cells remains speculative, occurring either as a mutation of a single stem cell or as a synchronous malignant transformation of two epithelial cell types exposed to a particular carcinogenic factor(s). Adenocarcinomas containing endocrine cells appear to be as biologically aggressive as the usual adenocarcinomas of the stomach and therefore should be treated in a like manner.

Small-cell carcinoma of the rectum. Clinicopathologic study

Three cases of small-cell carcinoma of the rectum are presented. Our conclusions are as follows: small-cell carcinoma and carcinoid tumor of the rectum might have a common origin; indications for surgical intervention for small-cell carcinoma of the rectum should be considered seriously; small-cell carcinoma of the rectum should be classified as an aggressive type of rectal tumor that metastasizes easily to distant organs.

Gastric small-cell undifferentiated carcinoma with adeno and squamous cell carcinoma components

A unique gastric tumor is reported. A large portion of the tumor consisted of a diffuse sheet of undifferentiated cells reminiscent of a small cell undifferentiated carcinoma. The tumor cells showed a few dense core granules and a poorly developed attachment apparatus by electron microscopy. In addition, small portions of the tumor showed adenocarcinoma and squamous cell carcinoma. Another noteworthy finding was that some of the metastatic hepatic nodules consisted of relatively monotonous polygonal cells with a distinct cord-like pattern showing argentaffinity and argyrophilia which were indicative of an atypical carcinoid. This case is a rare example of a gastric tumor with differentiation towards endocrine as well as adeno and squamous cell carcinoma.

Extrapulmonary oat cell carcinoma

Primary extrapulmonary tumors with histologic features indistinguishable from bronchogenic oat cell carcinoma are appearing with increasing frequency in the literature. These tumors have been described in the esophagus, stomach, pancreas, larynx, hypopharynx, salivary glands, nasal cavity and paranasal sinuses, thymus, small and large bowel, uterine cervix, endometrium, breast, prostate, urinary bladder, and skin. It is now widely believed that oat cell carcinoma is a poorly differentiated counterpart of carcinoid tumor and that both originate from an endocrine cell system. In this article, the authors review all cases of extrapulmonary oat cell carcinomas, which they were able to find in the English literature, and report personally studied examples of these tumors, occurring in the esophagus, stomach and urinary bladder. A closely related, if not identical, tumor arising in the skin is also described. It is emphasized that a wider recognition of these tumors is likely to lead to their more frequent diagnosis and possible treatment.

Histopathology of gastric carcinoids: a survey of 42 cases

An unselected series of 42 gastric carcinoids has been reviewed. Clinically the tumours simulated common gastric lesions including ulcer, polyp and carcinoma. No endocrine symptoms were identified. The tumours were most frequent in the body of the stomach and in 25% in that site were multiple. Morphologically most tumours when classified according to Soga (1974) demonstrated a mixed growth pattern. Six tumours displayed an atypical morphology (type D): they were larger and metastasized more frequently than the rest of the tumours. Six tumours contained a few scattered argentaffinic cells but the others were negative indicating negligible serotonin secretion in only a few cases. The Grimelius argyrophilic reaction was positive in most cells in all tested tumours except in three, two of which showed atypical morphology (type D). It is suggested that gastric carcinoids with a type D morphology or a minority cell population of argyrophil cells are dedifferentiated carcinoids which are biologically nearer to gastric carcinomas. The most frequent clinicopathological correlation was achlorhydria linking pernicious anaemia and gastric carcinoids. This indicates pathogenetic similarities between gastric carcinoids and gastric carcinomas.

Solid carcinomas of the stomach. A combined histochemical, light and electron microscopic study

Twenty cases of solid carcinoma of the stomach (SCS) were studied light and electron microscopically and histochemically. On the histologic, histochemical, and ultrastructural bases they were divided into three subgroups: mucin-secreting carcinomas (MSC) (12 cases); neuroendocrine tumors (NET) (five cases); and composite tumors (CT) (three cases). Histochemically, mucin was detectable at high intensity in most cases of MSC and ultrastructurally, the mucin granules, the number of which varied considerably from cell to cell, showed prominent pleomorphism with varying degree of maturity. Uniformly round neuroendocrine granules were demonstrable in all of the NET cases and in two cases of CT. The argyrophilic stain was negative in two cases of NET, whereas it was positive in three cases of MSC. Thus, there was a discrepancy between the silver nitrate reduction intensity and the ultrastructural demonstrability of neuroendocrine granules. Histologically, combined occurrence of some nuclear palisading of basal cells and rosette-like arrangement without evident glandular formation was specific to NET and this provides a helpful basis for the light microscopic differentiation of this tumor from other type tumors.

Argyrophil cells in early gastric carcinoma: an immunohistochemical and ultrastructural study

Eighteen argyrophil cell carcinomas in 101 early gastric carcinomas were explained histologically, ultrastructurally, and immunohistochemically for polypeptides, carcinoembryonic antigen (CEA), lysozyme, and human chorionic gonadotrophin (hCG). Seven of these 18 tumors had gastrin, and two of seven tumors also contained somatostatin. In all of these 18 tumors CEA were demonstrated. Seven had lysozyme and five of seven tumors also contained gastrin; hCG were present in four of the 18 tumors and two of four tumors had gastrin, CA, mucin, and lysozyme simultaneously. Argentaffin cells were found in seven of 18 tumors. Of the above seven tumors containing gastrin, three had argentaffin cells. Ultrastructurally, several types of secretory granules were noted and tumor cells resembling D1- or P cells were present in nine of the 18 tumors. Macroscopically, many of the tumors showed IIc or IIc + III type. Histologically, the 18 tumors consisted of six well differentiated adenocarcinomas and 12 poorly differentiated adenocarcinomas including signet-ring cell carcinoma. These 12 tumors frequently developed in the stomach of young females. In view of our previous investigations, it was suggested that the IIc-type argyrophil cell carcinoma histologically showing poorly differentiated adenocarcinoma may be related to scirrhous carcinoma of the stomach.

Scirrhous argyrophil cell carcinoma of the stomach with multiple production of polypeptide hormones, amine, CEA, lysozyme, and HCG

Sixteen argyrophil cell carcinomas in 59 gastric scirrhous carcinomas were examined histologically, ultrastructurally, and immunohistochemically for polypeptide hormones, CEA, lysozyme, and HCG. In nine of these 16 tumors, polypeptides such as gastrin, somatostatin, and glucagon were demonstrated. Six of these nine tumors contained all three hormones, and three of these six tumors also had argentaffin cells. In all of these 16 tumors CEA were observed. Eight of them had CEA, lysozyme, and acid mucin synchronously. Of the above six tumors containing three peptides, three produced focal HCG. Ultrastructurally, several types of secretory granules were noted. Histologically, these 16 tumors showed poorly differentiated adenocarcinomas or signet ring cell carcinomas. Macroscopically, generalized type was 11 and localized type five. No hormonal syndrome was detected in any of the patients. It was suggested that these scirrhous argyrophil cell carcinomas of the stomach with the multifunction originate from totipotent immature cells of endodermal origin.

Carcinoma of the larynx with mucosubstance production and neuroendocrine differentiation: an ultrastructural and immunohistochemical study

Primary neuroendocrine tumors of the larynx appear to be extremely rare. We report a case of well-differentiated neuroendocrine carcinoma arising in the larynx of a 61-year-old white woman. This case was initially diagnosed as a lymph node metastasis in the neck from an unknown primary carcinoma. Extensive workup subsequently revealed that the larynx was the primary site of the tumor. An electron microscopic study of both the primary and metastatic tumors showed numerous neurosecretory-type granules. Immunohistochemical studies revealed positive immunoreactivity against calcitonin, somatostatin, and ACTH. However, the tumor also displayed focal exocrine differentiation and mucosubstance production. The patient underwent a supraglottic laryngectomy and radical neck dissection and was free of tumor 22 months postoperatively.

Neuroendocrinoma of the jejunum: electron microscopic and biochemical analysis

A 56-year-old woman presented with a sudden, severe hemorrhage per rectum. Angiography localized a jejunal tumor, which was excised. Light microscopy suggested a neuroendocrine tumor, but neither a smooth muscle tumor nor a lymphoma could be excluded. Electron microscopy showed dense cored, single membrane bound secretory granules 150--220 nm in diameter; myofilaments were not observed. Biochemical analysis of tumor tissue yielded considerable amounts of catecholamines. VMA, 5-HIAA, and metanephrines. These combined ultrastructural and biochemical observations establish the diagnosis of neuroendocrine tumor; however, in this case neither type of information is sufficiently specific to define the tumor as either a paraganglioma or a carcinoid. Although paraganglia and mucosal endocrine cells in the GI are currently thought to constitute distinct cell types, they share numerous structural and functional properties, and they are both thought to be part of the APUD cell system. These parallels and similarities are shared by the neoplasms derived from them which often display features of both. In the absence of specific granule types or specific substances isolated from tumor tissue, only the application of specific immunocytochemistry techniques may allow the precise "functional" classification of such tumors.

Neuroendocrine carcinomas of the esophagus

Of a total of 928 primary esophageal cancers, 16 cases of "undifferentiated" esophageal carcinoma were isolated. The topographic and age distributions as well as the clinical presentation and evolution of these tumors were basically similar to those of the usual esophageal squamous carcinoma. By light microscopy, the tumors were comprised exclusively or predominantly of small, round-to-fusiform cells. The cytoplasm appeared scanty and the nuclei were comparatively large and hyperchromatic. Mitotic activity was prominent. Four of the sixteen neoplasms showed occasional foci of squamous differentiation. Argyrophilic cells were seen in all cases, although their number and distribution were variable. Occasional mucosubstance droplets were present in 2 cases. Argentaffin and amyloid stains were negative in all tumors. Ultrastructural studies revealed variable numbers of granules consisting of a dense core, a pale halo, and a single, delimiting membrane; these measured between 80 and 220 nm in diameter. Four of the sixteen cases displayed conspicuous tonofilament bundles and rare keratohyalin granules. The predominant ultrastructural common denominator of these tumors was the presence of characteristic neurosecretory-type granules; thus, their classification as neuroendocrine carcinomas would appear justified. Nevertheless, the abundant tonofilaments and the rare keratohyalin granules and mucosubstance droplets seen in several cases indicate that some of these epithelial cancers possess and express variable capabilities toward multidirectional differentiation.

Oat cell carcinoma of the stomach

An autopsy case of oat cell carcinoma arising in the stomach is described. The histology of the tumor was similar to that of ordinary oat cell carcinoma of the lung, and the secretory granules were identified by electron microscopy. Except for the direct invasion of the perigastric region and metastasis of the liver, no tumor was found in the lungs or any other organs. The occurrence of this type of tumor in the stomach as in other extrapulmonary organs provides supplemental evidence for the existence of the carcinoid-oat cell carcinoma group, recently established in the lung.