Endocrine tumours of the stomach

Modern Management of Gastric Neuroendocrine Neoplasms

OPINION STATEMENT

Gastric neuroendocrine neoplasms (G-NENs) are a heterogeneous group of tumors that broadly fall into two groups. The first group, driven by oversecretion of gastrin, are generally multifocal, small, and behave indolently with a low (but non-zero) risk of progression and metastatic spread. They are conventionally categorized into type 1, with endogenous gastric-based overproduction of gastrin, and type 2 G-NEN, with overproduction of gastrin from an extra-gastric gastrin-secreting tumor. The second group, termed type 3 G-NEN, occur spontaneously and are potentially more aggressive, having a clinical course analogous to other neuroendocrine tumors of the gastrointestinal tract. Type 1 G-NEN can be managed with endoscopic surveillance and resection of visible lesions with great success, reserving surgery for the rare high-risk lesion, whereas surgical resection of the causative gastrin-secreting tumor in type 2 G-NEN is usually curative. Type 3 G-NEN is usually managed with formal surgical resection but there is growing evidence that limited surgery or even endoscopic resection in appropriately selected patients with low risk is both safe and effective. A novel subtype of G-NEN, associated with long-term proton pump inhibitor usage, is increasing in incidence. The pathophysiology seems to parallel type 1 G-NEN. In the setting of metastatic disease, which can occur in any subtype but is most common by far in type 3 G-NEN, the lack of trial data unique to G-NEN results in extrapolation of strategies and agents for treatment of non-gastric neuroendocrine disease. The rapid pace of development in this area is likely to benefit the metastatic G-NEN patient as well. As treatment is predicate on type of G-NEN, establishing the etiology of the lesion is crucial but growing knowledge of G-NEN pathophysiology and close collaboration between pathologists, gastroenterologists, radiologists, surgeons, and oncologists have enabled a growing trend towards de-escalation and less-invasive treatment paradigms.

Gastric neuroendocrine neoplasms: A review

Gastric neuroendocrine neoplasms (g-NENs) or neuroendocrine tumors are generally slow-growing tumors with increasing incidence. They arise from enterochromaffin like cells and are divided into four types according to clinical characteristic features. Type 1 and 2 are gastrin dependent, whereas type 3 and 4 are sporadic. The reason for hypergastrinemia is atrophic gastritis in type 1, and gastrin releasing tumor (gastrinoma) in type 2 g-NEN. The diagnosis of g-NENs needs histopathological investigation taken by upper gastrointestinal endoscopy. g-NENs are positively stained with chomogranin A and synaptophysin. Grading is made with mitotic index and ki-67 proliferation index on histopathological analysis. It is crucial to discriminate between types of g-NENs, because the management, treatment and prognosis differ significantly between subtypes. Treatment options for g-NENs include endoscopic resection, surgical resection with or without antrectomy, medical treatment with somatostatin analogues, netazepide or chemotherapy regimens. Follow-up without excision is another option in appropriate cases. The prognosis of type 1 and 2 g-NENs are good, whereas the prognosis of type 3 and 4 g-NENs are close to the prognosis of gastric adenocancer.

Neuroendocrine Tumors of the Gastrointestinal Tract and Pancreas

Neuroendocrine neoplasms (NENs) of the gastrointestinal (GI) tract and pancreas are a rare and heterogeneous group of neoplasms characterized by common cellular features as well as unique site-specific traits. GI and pancreatic NENs are much rarer than the more common adenocarcinomas arising at these sites. However, the incidences of GI and pancreatic NENs have increased significantly, particularly in the stomach and common site, followed by rectum, appendix, colon, and stomach. Pancreatic NENs are also uncommon, with fewer than 1 per 100,000, accounting for 1% to 2% of all pancreatic neoplasms.

An atypical type I gastric neuroendocrine tumor

BACKGROUND

Gastric neuroendocrine tumors (GI-NETs) are rare lesions, usually discovered incidentally during endoscopy. Based on their pathology, there are 4 types of GI-NETs. Type I are multiple small polypoid lesions with central ulceration located in the gastric body or the fundus, associated with atrophic gastritis usually noninvasive and very rarely metastatic. We report on a rare case of a gastric NET arising from the muscularis propria layer of the pyloric ring.

CASE REPORT

We present the case of a 65-year old woman with a history of alcoholic cirrhosis, investigated for melena. Upper endoscopy revealed a 30 mm submucosal pedunculated polypoid lesion located on the pylorus protruding in the duodenum, with normal overlying mucosa, fundic gastric atrophy and multiple small polyps at this level, with no active bleeding. CT scan did not reveal any distant metastases. An ultrasound endoscopy was performed, and a round hypoechoic heterogeneous solitary mass, evolving from the pyloric muscle was described. Considering a 30-mm tumor evolving from the gastric muscle layer in the absence of local invasion and with no distant metastases we decided against an endoscopical resection and we referred the patient to surgery. A laparoscopic wedge resection was performed. The pathology report described a 30/25 mm welldifferentiated neuroendocrine tumor invasive in the muscularis mucosa (pT3).

CONCLUSIONS

Usually, type I neuroendocrine tumors are located in the body or the fundus of the stomach without submucosal invasion. The interesting feature in our case was that the tumor originated from the pylorus, making it an atypical presentation for a neuroendocrine tumor.

Imaging of secretory tumors of the gastrointestinal tract

Gastrointestinal secretory tumors, or gastroenteropancreatic neuroendocrine tumors, encompass a wide array of endocrine cell tumors. The significance of these tumors lies in their ability to alter physiology through hormone production as we well as in their malignant potential. Functioning tumors may present earlier due to symptomatology; conversely, non-functioning tumors are often diagnosed late as they reach large sizes, causing symptoms secondary to local mass effect. Imaging aids in the diagnosis, staging, and prognosis and provides key information for presurgical planning. Although most of these tumors are sporadic, some are associated with important syndromes and associations, knowledge of which is critical for patient management. In this article, we provide an overview of secretory and neuroendocrine tumors of the GI tract and pancreas.

Histological characterisation and prognostic evaluation of 62 gastric neuroendocrine carcinomas

AIM OF THE STUDY

To determine the significance of expression of synaptophysin, chromogranin A, and Ki-67 and their association with clinicopathological parameters, and to find out the possible prognostic factors in gastric neuroendocrine carcinoma (G-NEC).

MATERIAL AND METHODS

We investigated the immunohistochemical features and prognosis of 62 G-NECs, and evaluated the association among expressions of synaptophysin, chromogranin A, and Ki-67, clinicopathological variables, and outcome.

RESULTS

Chromogranin A expression was found more commonly in small-cell NECs (9/9, 100%) than in large-cell NECs (27/53, 51%) (p = 0.008). No statistical significance was found in Ki-67 (p = 0.494) or synaptophysin (p > 0.1) expression between NEC cell types. Correlation analyses revealed that Ki-67 expression was significantly associated with mid-third disease of stomach (p = 0.005) and vascular involvement (p = 0.006), and had a trend of significant correlation with tumour relapse (p = 0.078). High expression of chromogranin A was significantly associated with histology of small-cell NECs (p = 0.008) and lesser tumour greatest dimension (p = 0.038). The prognostic significance was determined by means of Kaplan-Meier survival estimates and log-rank tests, and as a result, early TNM staging and postoperative chemotherapy were found to be correlated with longer overall survival (p < 0.05). Univariate analysis revealed associations between poor prognosis in NECs and several factors, including high TNM staging (p = 0.048), vascular involvement (p = 0.023), relapse (p = 0.004), and microscopic/macroscopic residual tumour (R1/2, p < 0.001). In a multivariate analysis, relapse was identified as the sole independent prognostic factor.

CONCLUSIONS

No significant correlation between survival and expression of synaptophysin, chromogranin A, or Ki-67 has been determined in G-NECs. Our study indicated that early diagnosis, no-residual-tumour resection, and postoperative chemotherapy were possible prognostic factors.

Imaging of carcinoid tumors: spectrum of findings with pathologic and clinical correlation

Carcinoid tumors are primary malignant neoplasms that arise from neuroendocrine cells. These cells are located throughout the body, resulting in many possible locations for the development of carcinoid tumor. The most common primary location is the gastrointestinal tract, followed by respiratory and thymic carcinoids. The presentations of these tumors are variable depending on their location, aggressiveness, production of functional peptides, and tendency to invade or metastasize. Carcinoid tumors can be imaged by various modalities including gastrointestinal studies, ultrasound, computed tomography, and magnetic resonance imaging as well as nuclear medicine studies (radioactive octreotide). In this review, we illustrate the spectrum of imaging features of carcinoid tumors in various locations of the human body.

Sporadic gastric carcinoid tumor successfully treated by two-stage laparoscopic surgery: A case report

We report a case of sporadic gastric carcinoid tumor successfully treated by two-stage laparoscopic surgery. A 38-year old asymptomatic woman was referred to our hospital for evaluation of a submucosal tumor of the stomach. Endoscopic examination showed a solitary submucosal tumor without ulceration or central depression on the posterior wall of the antrum and biopsy specimens were not sufficient to determine the diagnosis. Endoscopic ultrasound revealed a tumor nearly 2 cm in diameter arising from the muscle layer and a computed tomography scan showed the tumor enhanced in the arterial phase. Laparoscopic wedge resection was performed for definitive diagnosis. Pathologically, the tumor was shown to be gastric carcinoid infiltrating the muscle layer which indicated the probability of lymph node metastasis. Serum gastrin levels were normal. As a radical treatment, laparoscopy-assisted distal gastrectomy with regional lymphadenectomy was performed 3 wk after the initial surgery. Finally, pathological examination revealed no lymph node metastasis.

Typical carcinoids and neuroendocrine carcinomas of the stomach: differing clinical courses and prognoses

BACKGROUND

Gastric endocrine tumors are usually classified as 3 types of well-differentiated endocrine tumors (typical carcinoids or carcinoids) and poorly differentiated carcinomas (neuroendocrine carcinomas [NECs]).

METHODS

From 1993 to 2008, 97 patients (73 men and 24 women) were diagnosed with gastric neuroendocrine tumors at the Asan Medical Center.

RESULTS

Of the 45 patients with typical carcinoids, 37 underwent surgery (eg, endoscopic resection). Of the 52 patients with NECs, 43 underwent surgery (eg, radical gastrectomy). One patient died of recurrence of the typical carcinoids, whereas 26 patients with NECs died of related diseases (P < .05). The rates of survival and recurrence did not significantly differ by type of typical carcinoid (P > .05).

CONCLUSIONS

Regardless of the type, carcinoids that are not yet advanced can be effectively treated with minimal endoscopic or laparoscopic surgery. However, all NECs and advanced carcinoids should be treated with radical gastrectomy.

Treatment of gastric carcinoids

Gastric carcinoid tumors are uncommon, but their percentage among all gastric malignancies has increased to 1.8%. Although they are most often discovered incidentally during endoscopy, gastric carcinoids can present with abdominal pain, bleeding, or symptoms related to the secretion of bioactive substances, most commonly histamine. Gastric carcinoids originate from the foregut and are derived from histamine-containing enterochromaffin-like (ECL) cells. Type I gastric carcinoid, the most common, exhibits slow growth and benign behavior. It occurs within the setting of chronic atrophic gastritis with achlorhydria-induced hypergastrinemia. Gastrin acts directly on ECL cells to induce hyperplasia, dysplasia, and, eventually, neoplasia. Type II gastric carcinoid, the least common type, occurs in patients with gastrinoma-associated multiple endocrine neoplasia syndrome-type 1 (MEN-1). The overall survival is related more to the underlying MEN-1 syndrome than to the gastric carcinoid. Rodents readily develop gastric carcinoid tumors in response to hypergastrinemia. However, in humans, other factors in addition to hypergastrinemia, such as pernicious anemia or MEN-1, must be present, implying that a genetic predisposition is necessary for the development of these tumors. Type III or sporadic gastric carcinoids exhibit a more malignant behavior, with overall 5-year survival rates of less than 50% and normal serum gastrin concentrations. Treatment of all types of gastric carcinoids is predicated upon accurate classification and staging. Radiolabeled somatostatin analogues are superior to conventional radiologic imaging techniques in detecting both primary and metastatic lesions. Treatment of choice for localized disease is excision, either endoscopically or surgically. Antrectomy, by eliminating the trophic effect of gastrin, can be useful for select type I carcinoids. Long-acting somatostatin analogues are excellent palliative agents.

Gastrointestinal carcinoid tumors in rare locations: imaging findings

In this article, we present radiological findings in three patients with mesenteric, gastric, and rectal carcinoid tumors. More than 90% of the carcinoid tumors arise in the gastrointestinal system (GIS). They comprise 2% of all GIS tumors and are usually located in the small intestine and the appendix. On the other hand, gastric, rectal, and mesenteric carcinoids are rare. Better knowledge of radiological features of carcinoid tumors in rare locations will prevent diagnostic delays and development of carcinoid syndrome.

Multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome: a prospective study of 107 cases and comparison with 1009 cases from the literature

In patients with multiple endocrine neoplasia type 1 (MEN1), the most common functional pancreatic endocrine tumor (PET) syndrome is Zollinger-Ellison syndrome (ZES). ZES has been well studied in its sporadic form (that is, without MEN1); however, there are limited data on patients with MEN1 and ZES (MEN1/ZES), and the long-term natural history is largely unknown. To address this issue we report the results of a prospective long-term National Institutes of Health (NIH) study of 107 MEN1/ZES patients and compare our results with those of 1009 MEN1/ZES patients in 278 case reports and small series in the literature. Patients were clinically, radiologically, and biochemically evaluated yearly for all MEN1 manifestations (mean follow-up, 10 yr; range, 0.1-31 yr). Compared with patients from the literature, the NIH MEN1/ZES patients more frequently had pituitary (60%) and adrenal (45%) disease and carcinoid tumors (30%), but had equal frequency of hyperparathyroidism (94%), thyroid disease (6%), or lipomas (5%). Twenty-five percent of both the NIH and the literature patients lacked a family history of MEN1; ZES was the initial clinical manifestation of MEN1 in 40%. ZES onset preceded the diagnosis of hyperparathyroidism in 45%. However, ZES was rarely (8%) the only initial manifestation of MEN1 if careful testing was done. ZES occurred before age 40 years in 50%-60% of the current patients, in contrast to older studies. The diagnosis of ZES is delayed 3-5 years from its onset and is delayed as long as in sporadic ZES cases. Pituitary disease and carcinoid tumors (gastric > bronchial, thymic) are more frequent than generally reported, whereas a second functional PET is uncommon. In patients with MEN1/ZES without a family history of MEN1, the MEN1 manifestations are not as severe. This study shows that MEN1/ZES patients differ in many aspects from those commonly reported in older studies involving few MEN1/ZES patients. In this study we have identified a number of important clinical and laboratory features of MEN1/ZES that were not previously appreciated, which should contribute to earlier diagnosis and improve both short- and long-term management.

Carcinoid tumors of the stomach

Interest in gastric carcinoid tumors has in recent time amplified considerably as the understanding of both their biological background and clinical significance has developed. The increase in identification associated with the widespread availability of upper gastrointestinal endoscopy has facilitated diagnosis. In addition concern related to the consequences of long-standing hypergastrinemia generated by the use of potent acid-suppressive medications has augmented both clinical and scientific focus on gastric neuro endocrine issues. The elucidation of the regulatory mechanisms of the progenitor cell (ECL cell) of the gastric carcinoid tumor, the refinement of a pathological grading system for ECL cell proliferation, and the availability of specific immunohistologic identification techniques have further amplified the characterization of this lesion. Although the putative malignant potential of gastric carcinoids may ultimately be of only modest concern in a background of hypergastrinemia its relationship to gastric adenocarcinoma is still enigmatic and worthy of further consideration. This review will describe the molecular interrelationship between low-acid states, gastrin, and ECL cell proliferation and will discuss the pathological classification of the distinct types of gastric carcinoid tumors. In addition, the clinical rationale of current diagnostic and therapeutic strategies will be examined, providing a logical basis for the formulation of appropriate management strategies for patient care.

Gastric carcinoid tumors as a consequence of chronic hypergastrinemia: spiral CT findings

The development of gastric carcinoid tumors is a rare but recognized complication of prolonged, severe hypergastrinemia. We present 2 patients with elevated gastrin levels who developed gastric carcinoid tumors and the CT findings are reviewed.

Gastric neuroendocrine neoplasms: tumour clonality and malignancy-associated large X-chromosomal deletions

Type I gastric carcinoid tumours associated with corporal (body of stomach) atrophic gastritis (CAG) are benign tumours developing as the final step of a hyperplastic precursor sequence. The neoplastic nature of these tumours has been assumed but never proved. Type III gastric carcinoid tumours and neuroendocrine carcinomas are malignant neoplasms without known precursor lesions. To assess the neoplastic nature of type I carcinoids, the clonal status of 35 tumours from 23 female patients was investigated using the human androgen receptor (HUMARA) gene test, which is based on the pattern of X-chromosome inactivation. For comparison, the same test was also performed on four type III carcinoids and two neuroendocrine carcinomas. DNA extracted from paraffin sections was digested with Hha I restriction enzyme and then amplified by polymerase chain reaction (PCR) using established HUMARA primers. The PCR products were analysed in an automated DNA sequencer. In a complementary analysis of the same tumours, loss of heterozygosity (LOH) on the X chromosome was studied using three polymorphic markers (DXS989, DXS1003, DXS1192) in a PCR-microsatellite-based technique. After exclusion of non-informative cases, 14 of 16 type I carcinoids were found to be monoclonal on the basis of the pattern of X-chromosome inactivation. Monoclonality was also documented in one of three type III carcinoids and in the single neuroendocrine carcinoma, on the basis of LOH at the HUMARA locus, which per se can be regarded as evidence for clonality. Extensive LOH of the X chromosome involving at least two markers, was found in all metastasizing tumours (two type III carcinoids and two neuroendocrine carcinomas), but in none of the 27 benign carcinoids of types I and III. These results indicate that most type I carcinoids are true monoclonal neoplasms and that malignant evolution in gastric neuroendocrine tumours is associated with extensive allelic deletion of one X chromosome.

Tumores neuroendócrinos do trato gastrointestinal

Os tumores neuroendócrinos (TNE) já foram considerados raridades. Atualmente, através de novas técnicas para seu reconhecimento, tem-se identificado um número crescente destas neoplasias, sendo possível estratificá-las em subgrupos, expandindo o espectro dos neoplasmas neuroendócrinos e sua importância na prática cirúrgica atual. A imunocitoquímica, a dosagem de peptídeos e os modernos métodos de imagem proporcionam informações imprescindíveis para um diagnóstico acurado e o tratamento adequado. Este artigo tem por objetivo revisar aspectos referentes aos tumores neuroendócrinos do trato gastrointestinal relativos à história, fisiopatologia, classificação atualizada, diagnóstico e tratamento.

[Multiple endocrine neoplasia Type I. Diagnosis and therapy in a case with classical family history]

BACKGROUND

A classical family history, representative of the multiple endocrine neoplasia type I (MEN I) syndrome, is reported to illustrate the clinical manifestations, diagnostic procedures and therapeutic modalities of the various endocrine disorders of this syndrome.

DIAGNOSIS

Today genetic analysis clearly identifies gene carriers. In these patients screening of all involved endocrine organs (parathyroid, pituitary, pancreas) at regular time intervals is necessary because also at higher ages additional endocrine manifestations may develop. Due to consequent screening the age at time of diagnosis was reduced by 10 to 20 years. As a consequence the rate of malignancy of pancreatic endocrine tumors which is the limiting factor with regard to long-term prognosis was reduced to about one third. At present it is not known whether this procedure can also increase the survival rate of MEN I patients as could be demonstrated in the MEN II syndrome.

Classification of gastric neuroendocrine tumors and its clinicopathologic significance

AIMS: To study the pathologic classification of gastric neuroendocrine tumors and its clinicopatho-logic significance.

METHODS: Paraffin-embedded sections of 52 gastric neuroendocrine tumors including 42 carcinoid tumors, and 10 cases of neuroendocrine carcinoma from 326 patients who underwent resection of stomach carcinomas were studied by immunohistochemical methods including 10 endocrine markers or hormones antibodies and endocrine cells in gastric neuroendocrine tumors and extratumoral mucosa were observed under electromicroscope.

RESULTS: The 52 gastric neuroendocrine tumors were divided into three types: ① Gastrin dependent type of carcinoid (26 cases) accompanied by chronic atrophic gastritis (CAG) and tumor extension limited to the mucosa or submucosa complicated with hypergastrinemia and G cell hyperplasia. This type was consistently preceded by and associated with generalized proliferation of endocrine cells in the extratomoral fundic mucosa. ② Non-gastrin dependent type of carcinoids (16 cases) associated with neither CAG nor hypergastrinemia. This type was more aggressive; and ③ Neuroendocrie carcinomas (10 cases), which are highly aggressive tumors.

CONCLUSIONS: A correct identification of different types of gastric endocrine tumors has major implications for the treatment and prognosis of the patients.

Aggressive forms of gastric neuroendocrine tumors in multiple endocrine neoplasia type I

In recent classifications of gastric endocrine tumors, tumors arising in patients with multiple endocrine neoplasia type 1 (MEN-1) are regarded to be regulated by the concomitant hypergastrinemia resulting from to pancreatic or, most commonly, duodenal gastrinomas and to have a benign behavior. In this article, we report on two cases of MEN-1 gastric neuroendocrine tumors having a fatal course. Case 1 was a young male with hyperparathyroidism and Zollinger-Ellison syndrome and with florid development of multiple gastric carcinoids and multiple duodenal gastrinomas. Metastases occurred in the liver, of exclusive gastric origin, in periduodenal lymph nodes, of exclusive duodenal origin, and in perigastric lymph nodes, of mixed origin. The patient died 48 months after diagnosis. Case 2 was an adult female patient with hyperparathyroidism, adrenocortical disorders, and gastric tumors but no hypergastrinemia. The patient died 3 months after tumor diagnosis. At autopsy, the stomach showed multiple benign carcinoids and two independent neuroendocrine carcinomas not reported before in MEN-1 and massively metastatizing to lymph nodes, liver, and peritoneum. Multiple islet cell tumors mostly producing pancreatic polypeptide were found, whereas gastrinomas were seen in neither the pancreas nor the duodenum. Allelic losses at the MEN-1 gene locus in chromosome 11q13, the mechanism responsible for tumor development in MEN-1 syndrome, were demonstrated in the carcinoid tumors of case 1 and in the neuroendocrine carcinoma of case 2. We conclude that gastric neuroendocrine tumors in patients with MEN-1 may have a poor outcome, they have the same genetic mechanism as MEN-1 tumors in other organs, and they may be independent of the trophic effect of hypergastrinemia.