Carlo Capella

Revised Classification of Neuroendocrine Tumors of the Lung, Pancreas and Gut

The general use of the term carcinoid for the classification of neuroendocrine tumors has become increasingly difficult during recent years. First, its definition and prognosis varies from site to site. Second, its traditional definition does not cover the whole morphological and biological spectrum of neuroendocrine tumors known today. We therefore propose new classifications of the neuroendocrine tumors of the lung, pancreas, stomach, duodenum, jejunum-ileum, appendix and colorectum. These classifications use a common framework and attempt to consider the morphological, functional and biological features of these tumors.

Mucinous cystic tumors of the pancreas: clinicopathological features, prognosis, and relationship to other mucinous cystic tumors

The clinicopathological features of 56 patients with mucinous cystic tumors (MCTs) of the pancreas were studied. Particular attention was paid to the prognosis of MCTs and the relationship to their ovarian, hepatic, and retroperitoneal counterparts. To distinguish MCTs from pancreatic intraductal papillary-mucinous tumors, MCTs were defined as tumors lacking communication with the duct system and containing mucin-producing epithelium, usually supported by ovarian-like stroma. All 56 tumors occurred in women (mean age 48.2 years) and were preferentially (93%) located in the body and tail of the pancreas. In accordance with the WHO classification, MCTs were divided into adenomas (n = 22), borderline tumors (n= 12), and noninvasive and invasive carcinomas (n = 22). Survival analysis revealed the extent of invasion to be the most significant prognostic factor (p<0.0001). Malignancy correlated with multilocularity and presence of papillary projections or mural nodules, loss of ovarian-like stroma, and p53 immunoreactivity. Stromal luteinization with expression of tyrosine hydroxylase, calretinin, or alpha inhibin was found in 66% of the cases. We conclude that the biologic behavior of MCTs is predictable on the basis of the extent of invasion. The similarities (i.e. gender, morphology, stromal luteinization) between pancreatic MCT and its ovarian, hepatobiliary, and retroperitoneal counterparts suggest a common pathway for their development.

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.

Eradication of Helicobacter pylori Infection in Primary Low-Grade Gastric Lymphoma of Mucosa-Associated Lymphoid Tissue

Low-grade gastric lymphoma of mucosa-associated lymphoid tissue (MALT) is an uncommon tumor with an indolent natural history and prolonged confinement to the site of origin. Its morphologic appearance is characterized by prominent and often multifocal lymphoepithelial lesions showing dense, diffuse infiltrates of centrocyte-like cells within the lamina propria [1]. B-cell monoclonality can often be shown by either immunocytochemical or molecular methods [2]. A close association has been suggested between gastric MALT lymphoma and the presence of certain strains of Helicobacter pylori, which are found in more than 90% of patients with gastric MALT lymphoma [3]. Regression of this lymphoma after eradication of H. pylori was reported in 5 of 6 patients who received antibiotic therapy [2]. We analyzed the effects of antibiotic therapy for H. pylori infection in 26 patients with low-grade gastric MALT lymphoma. Our patients were from a geographic area (southern Switzerland and northern Italy) where the incidence of gastric tumors appears to be uncommonly high [4, 5]. Many patients with primary gastric lymphoma reside in northeastern Italy [6], a region geographically close and environmentally similar to the area in which our patients reside. Reasons for these disease clusters are not known. Methods Twenty-six patients (14 women, 12 men; median age, 60 years [range, 21 to 76 years]) with histologic diagnoses of localized (stage IE), primary, B-cell, low-grade gastric MALT lymphoma and H. pylori infection (diagnosed using endoscopic biopsy specimens) were entered into our study. Almost all patients had a prolonged history (as long as 4 years) of gastric symptoms before diagnosis of H. pylori infection, and most of them had already been given antacid medication, motility stimulant agents, or both. Before patients received treatment for H. pylori infection, the following staging procedures were done: physical examination, routine laboratory tests, chest radiographs, abdominal ultrasound or computed tomographic scans, endoscopic gastric biopsy specimens, and bone marrow biopsy specimens. Patients were treated for H. pylori infection for 2 weeks with amoxicillin (500 mg three times daily) plus metronidazole (400 mg three times daily) and colloidal bismuth (120 mg four times daily; 13 patients) or omeprazole (20 mg twice daily; 13 patients). Twenty patients were treated immediately after diagnosis of H. pylori infection, and 6 were treated after an observation period of several months (median, 5 months; range, 3 to 36 months) without endoscopic and histologic changes of the MALT lymphoma. One patient had a brief response to first-line combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP regimen), but the patient later had a local relapse. This patient still had histologic characteristics of low-grade gastric MALT lymphoma when treatment for H. pylori infection was given. To reevaluate the condition of the patients after treatment for H. pylori infection, biopsy specimens were obtained from any abnormal area in the stomach and randomly obtained from the rest of the stomach. These multiple (range, 8 to 20 specimens), random biopsy specimens of the gastric mucosa were obtained within 6 months of treatment (3 months for 19 patients, 4 months for 4 patients, and 6 months for the remaining 3 patients); patients were reevaluated every 3 to 6 months thereafter. The patients with persistent H. pylori infection had additional treatment for 2 weeks with a different regimen: omeprazole (20 mg twice daily), metronidazole (400 mg three times daily), and azithromycin (500 mg daily for 3 consecutive days every week). Restaging with chest radiographs and abdominal ultrasound was done again after 1 year. In 9 patients, a bone marrow biopsy specimen was obtained again after 6 months. Histologic responses were graded according to the histologic scoring system recently proposed for the diagnosis of gastric MALT lymphoma [2]. We considered a post-treatment score of 2 or less to be evidence of lymphoma regression. Binomial exact 95% CIs were calculated for outcome percentages. Results Complete eradication of H. pylori was initially achieved in 21 patients (81%; 95% CI, 61% to 93%); in the remaining 4 patients, second-line antibiotic treatment was needed to eradicate the microorganism. The overall eradication rate was therefore 96% (25 of 26 patients; 95% CI, 80% to 99%). After treatment for H. pylori infection, the median follow-up was 12 months (range, 3 to 36 months). One patient, treated after an observation period of 36 months without clinical or histologic change, showed persistent gastric infection and unchanged lymphoma features on biopsy specimens obtained 3 months after treatment. The patient received additional antibiotic treatment but has not been reevaluated with endoscopy. All but one of the patients were symptomatic at presentation; the main symptoms were pain (60% of patients), dyspepsia (30% of patients), and nausea and vomiting (7% of patients). One patient presented with gastrointestinal hemorrhage. Symptoms disappeared in 77% of patients or markedly diminished after antibiotic treatment. At the endoscopic evaluation done before treatment, 11 patients had gastric ulcers, 9 had endoscopic evidence of gastritis, and the remaining 6 had abnormal, congestive (hyperemic) gastric mucosa. In all patients, these endoscopic features improved after eradication of H. pylori infection and all of the ulcers healed, but only one patient had a complete recovery of the gastric mucosa. Histologic regression of the MALT lymphoma (Table 1) was observed in 15 patients (60%; CI, 39% to 79%) after H. pylori eradication, including the 1 patient who relapsed after chemotherapy. Five patients had complete disappearance of any histologic evidence of lymphoma (histologic score, 0 to 1), and 10 patients had residual lymphoid follicles but no longer had lymphoepithelial lesions (histologic score, 2). Three patients showed persistent suspicious, probably reactive, lymphoid infiltrate in the lamina propria (histologic score, 3) and were considered to have not responded to treatment. The other patients showed no change or only partial improvement in the lymphoma histologic pattern in repeat gastric biopsy specimens. Table 1. Effects of Helicobacter pylori Eradication on Gastric Mucosa-Associated Lymphoid Tissue Lymphoma Our study suggests that regression of the lymphoma may require a prolonged period. Only 8 patients showed histologic regression on the first biopsy specimen after antibiotic treatment, but when endoscopic specimens were obtained again 3 or more months later, regression was clearly evident in 7 additional patients. At a median follow-up of 12 months, all patients were alive and 14 of 15 responders, including the 1 patient who relapsed after chemotherapy, were free of lymphoma. A bone marrow specimen from 1 patient showed evidence of relapse shortly thereafter, with a response duration of only 4 months; however, no evidence of MALT lymphoma was found in repeat gastric biopsy specimens (histologic score, 2). Discussion A strong causal relation between H. pylori infection and gastritis, duodenal ulcer, or both has been shown; moreover, increasing epidemiologic and histopathologic evidence indicates a link between H. pylori infection and gastric tumors, both carcinomas [7] and lymphomas [3, 8]. Further, the ability of H. pylori to stimulate cellular proliferation in low-grade gastric MALT lymphoma has been reported [9], and eradication of H. pylori may inhibit the growth of the lymphoma [2]. The rarity of extra-abdominal spread low-grade gastric MALT lymphoma may also be partially explained by the role of H. pylori in the pathogenetic process [9]. Our data confirm, in a larger series of patients, the recent observations that eradication of H. pylori can lead to a regression of the lymphoma [2, 10] and further support the concept of a causal correlation between H. pylori infection and gastric lymphoma. The case of low-grade gastric MALT lymphomas is not the only one in which a bacterial infection has been implicated in the pathogenesis of a lymphoma. Antibacterial therapy has already been reported to be useful in the treatment of -chain disease (a small-intestinal lymphoma) [11], providing indirect evidence that bacteria may have a pathogenetic role in lymphomas. Only careful, prolonged follow-up will ascertain whether treatment for H. pylori can definitely cure gastric MALT lymphoma. Currently, this represents one of the many questions in the treatment of gastric lymphoma (others include those about the necessity for surgery and role of chemotherapy) [12]. Our data show that for low-grade MALT gastric lymphoma, an antibiotic treatment designed to eradicate H. pylori appears to be mandatory before further therapeutic options are considered. An international randomized trial will soon investigate whether it is beneficial to add cytotoxic chemotherapy to such an antibiotic treatment.

Intraductal papillary-mucinous tumours represent a distinct group of pancreatic neoplasms: an investigation of tumour cell differentiation and K-ras, p53 and c-erbB-2 abnormalities in 26 patients

Intraductal papillary growth of mucin producting hypersecreting, columnar cells characterizes a group of rare pancreatic exocrine neoplasms which we propose to call intraductal papillary-mucinous tumors (IPMT). We analysed the histopathology of 26 IPMT in relation to gastro-enteropancreatic marker expression, genetic changes and biology. Four IPMT showing only mild dysplasia were considered to be adenomas. Nine tumours displayed moderate dysplasia and were regarded as borderline. Severe dysplasia-carcinoma in situ changes were found in 13 IPMT which were therefore classified as intraductal carcinomas. Six of these carcinomas were frankly invasive and two of these had lymph node metastases. The invasive component resembled mucinous noncystic carcinoma in all but one tumour which showed a ductal invasion pattern. Immunohistochemically, an intestinal marker type was found in most carcinomas, while gastric type differentiation prevailed among adenomas or borderline tumours. K-ras mutations (seven at codon 12 and one at codon 13) were found in 31% of IPMT (2 adenomas, 1 borderline, 5 carcinomas). Nuclear p53 overexpression was detected in 31% of IPMT (6 carcinomas and 2 borderline IPMT) and correlated with p53 mutations (one at exon 8 and the other at exon 5) in two carcinomas. p53 abnormalities were unrelated to K-ras mutation. c-erbB-2 overexpression was observed in 65% of IPMT, with various grades of dysplasia. Twenty-two of 24 patients are alive and well after a mean post-operative follow-up of 41 months. Only two patients, both with invasive cancer at the time of surgery, died of tumour disease. It is concluded that pancreatic IPMT encompass neoplasms which, in general, have a favorable prognosis, but are heterogeneous in regard to grade of dysplasia and marker expression. Adenoma, borderline tumour, intraductal carcinoma and invasive carcinoma can be differentiated. p53 changes but not K-ras mutation or c-erbB-2 overexpression are related to the grade of malignancy. Most IPMT differ in histological structure, marker expression and behaviour from ductal adenocarcinoma.

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.

Endocrine cells of the gastric mucosa

Publisher Summary This chapter discusses the endocrine cells of the gastric mucosa. On ultrastructural and histochemical grounds, non-enterochromaffin (EC) endocrine cells of the gastrointestinal mucosa were classified as four or six independent cell types. Six distinct types of endocrine cells were added to the well-known EC cells. Staining patterns in light and electron microscopy amine histochemistry, and/or immunohistochemistry confirm the existence of this manifold population of endocrine cells. So far, biochemical and functional studies support the existence of four endocrine products, namely, 5-hydroxytryptamine (5HT), gastrin, histamine, and gastro glucagon. Thus, based on morphological evidence, more hormones than those presently reported are to be expected from the gastric mucosa. The interaction between endocrine cells and stimuli coming from the lumen or from blood and the nervous system; both the hypothesis of a direct interaction of luminal stimuli with the endocrine cell and a more complex mechanism involves specialized receptors and local or long central reflexes must be considered. The close dependence of most digestive functions on gastrointestinal hormones, the behavior of gastrointestinal endocrine cells in some digestive diseases associated with severe functional derangements such as peptic ulcer, malabsorption, pancreatitis, and the sequelae of surgical procedures affecting the alimentary canal—should be extensively investigated.

Immunomodulatory Function of Bone Marrow-Derived Mesenchymal Stem Cells in Experimental Autoimmune Type 1 Diabetes

Human clinical trials in type 1 diabetes (T1D) patients using mesenchymal stem cells (MSC) are presently underway without prior validation in a mouse model for the disease. In response to this void, we characterized bone marrow-derived murine MSC for their ability to modulate immune responses in the context of T1D, as represented in NOD mice. In comparison to NOD mice, BALB/c-MSC mice were found to express higher levels of the negative costimulatory molecule PD-L1 and to promote a shift toward Th2-like responses in treated NOD mice. In addition, transfer of MSC from resistant strains (i.e., nonobese resistant mice or BALB/c), but not from NOD mice, delayed the onset of diabetes when administered to prediabetic NOD mice. The number of BALB/c-MSC trafficking to the pancreatic lymph nodes of NOD mice was higher than in NOD mice provided autologous NOD-MSC. Administration of BALB/c-MSC temporarily resulted in reversal of hyperglycemia in 90% of NOD mice (p = 0.002). Transfer of autologous NOD-MSC imparted no such therapeutic benefit. We also noted soft tissue and visceral tumors in NOD-MSC-treated mice, which were uniquely observed in this setting (i.e., no tumors were present with BALB/c- or nonobese resistant mice-MSC transfer). The importance of this observation remains to be explored in humans, as inbred mice such as NOD may be more susceptible to tumor formation. These data provide important preclinical data supporting the basis for further development of allogeneic MSC-based therapies for T1D and, potentially, for other autoimmune disorders.

TNM Staging of Neoplasms of the Endocrine Pancreas: Results From a Large International Cohort Study

BACKGROUND Both the European Neuroendocrine Tumor Society (ENETS) and the International Union for Cancer Control/American Joint Cancer Committee/World Health Organization (UICC/AJCC/WHO) have proposed TNM staging systems for pancreatic neuroendocrine neoplasms. This study aims to identify the most accurate and useful TNM system for pancreatic neuroendocrine neoplasms. METHODS The study included 1072 patients who had undergone previous surgery for their cancer and for which at least 2 years of follow-up from 1990 to 2007 was available. Data on 28 variables were collected, and the performance of the two TNM staging systems was compared by Cox regression analysis and multivariable analyses. All statistical tests were two-sided. RESULTS Differences in distribution of sex and age were observed for the ENETS TNM staging system. At Cox regression analysis, only the ENETS TNM staging system perfectly allocated patients into four statistically significantly different and equally populated risk groups (with stage I as the reference; stage II hazard ratio [HR] of death = 16.23, 95% confidence interval [CI] = 2.14 to 123, P = .007; stage III HR of death = 51.81, 95% CI = 7.11 to 377, P < .001; and stage IV HR of death = 160, 95% CI = 22.30 to 1143, P < .001). However, the UICC/AJCC/WHO 2010 TNM staging system compressed the disease into three differently populated classes, with most patients in stage I, and with the patients being equally distributed into stages II-III (statistically similar) and IV (with stage I as the reference; stage II HR of death = 9.57, 95% CI = 4.62 to 19.88, P < .001; stage III HR of death = 9.32, 95% CI = 3.69 to 23.53, P = .94; and stage IV HR of death = 30.84, 95% CI = 15.62 to 60.87, P < .001). Multivariable modeling indicated curative surgery, TNM staging, and grading were effective predictors of death, and grading was the second most effective independent predictor of survival in the absence of staging information. Though both TNM staging systems were independent predictors of survival, the UICC/AJCC/WHO 2010 TNM stages showed very large 95% confidence intervals for each stage, indicating an inaccurate predictive ability. CONCLUSION Our data suggest the ENETS TNM staging system is superior to the UICC/AJCC/WHO 2010 TNM staging system and supports its use in clinical practice.

Lead-haematoxylin as a stain for endocrine cells - Significance of staining and comparison with other selective methods

SummaryA modification of MacConaills lead-haematoxylin has been found to stain several endocrine cells producing polypeptides and monoamines, particularly A and D cells of the pancreatic islet, thyroid C cells, gastro-intestinal enterochromaffin cells, gastric G and X cells, pituitary ACTH and MSH cells, adrenal medullary cells, and chemoreceptive cells of the carotid body. A careful comparison of the results of this method with those of HCI-basic dye method and of monoamine methods suggested that carboxyl groups of proteins may be the main binding site of lead-haematoxylin. Experiments with various pretreatments of tissue sections support such a hypothesis. The possibility that biogenic amines take also some part in the staining cannot be ruled out.