Endocrine pancreatic tumors

Endocrine secretory granule production is caused by a lack of REST and intragranular secretory content and accelerated by PROX1

Endocrine secretory granules (ESGs) are morphological characteristics of endocrine/neuroendocrine cells and store peptide hormones/neurotransmitters. ESGs contain prohormones and ESG-related molecules, mainly chromogranin/secretogranin family proteins. However, the precise mechanism of ESG formation has not been elucidated. In this study, we experimentally induced ESGs in the non-neuroendocrine lung cancer cell line H1299. Since repressive element 1 silencing transcription factor (REST) and prospero homeobox 1 (PROX1) are closely associated with the expression of ESG-related molecules, we edited the REST gene and/or transfected PROX1 and then performed molecular biology, immunocytochemistry, and electron and immunoelectron microscopy assays to determine whether ESG-related molecules and ESGs were induced in H1299 cells. Although chromogranin/secretogranin family proteins were induced in H1299 cells by knockout of REST and the induction was accelerated by the PROX1 transgene, the ESGs could not be defined by electron microscopy. However, a small number of ESGs were detected in the H1299 cells lacking REST and expressing pro-opiomelanocortin (POMC) by electron microscopy. Furthermore, many ESGs were produced in the REST-lacking and PROX1- and POMC-expressing H1299 cells. These findings suggest that a lack of REST and the expression of genes related to ESG content are indispensable for ESG production and that PROX1 accelerates ESG production.

Trial registration: Not applicable.

Immunohistochemical investigation of F344/N rat islet cell tumors from national toxicology program studies

In this study, we have investigated the immunoexpression of peptide hormones and mediators associated with human islet cell tumors in a group of proliferative islet cell lesions in F344 rats including islet cell hyperplasias, adenomas, and carcinomas, as defined by conventional histopathologic criteria. All proliferative islets expressed synaptophysin, although decreased expression intensity was observed in hyperplasias and adenomas. Most of the proliferative lesions expressed insulin, which generally decreased as lesions progressed toward malignancy. The distribution of glucagon, somatostatin, and gastrin-expressing cells was altered in proliferative islet lesions but did not comprise a large proportion of cells. Islet cell tumors were associated with increased nuclear expression of cyclin-dependent kinase 4 as well as increased proliferating cell nuclear antigen and decreased β-catenin expression. c-Myelocytomatosis oncogene expression was variable. This is the first study to describe the immunophenotype of islet cell tumors in the F344 rat and to show that islet cell tumors in the F344 rat exhibit similarities in protein expression to the human counterpart.

Co-existence of glucagonoma with recurrent insulinoma in a patient with multiple endocrine neoplasia-type 1 (MEN-1)

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors of the parathyroid glands, the anterior pituitary, and the endocrine pancreas. Our patient was a 58-year-old man who manifested typical features of MEN-1 including primary hyperparathyroidism, lung carcinoid, and lipomas and insulinoma. He was admitted to our hospital because of recurrent hypoglycemia and a growth of pancreatic tumors. The first operation for insulinoma was performed when he was 20 years old. We found a germline mutation of the MEN1 gene (E45G, exon 2) in this patient. According to these examinations and his clinical course, the patient was diagnosed as having a recurrence of insulinoma. He subsequently underwent surgery for the pancreatic tumors. The majority of these tumor cells were immunohistochemically positive for insulin and negative for glucagon. A few nodules showed immunohistochemical staining positivity for glucagon but they were negative for insulin. Although it is uncommon for patients with MEN1 to exhibit insulinoma and glucagonoma, this case suggests the need for careful analysis of pancreatic tumors in patients with MEN1.

Diagnostic value of CDX-2 and TTF-1 expressions in separating metastatic neuroendocrine neoplasms of unknown origin

Histomorphologic features and routine endocrine immunohistochemical (IHC) markers do not differentiate neuroendocrine tumors (NETs) in relation to their location, making it difficult to establish the site of origin of a metastatic neoplasm. Site-specific markers would be useful, particularly when examining small biopsies. CDX-2 and thyroid transcription factor-1 (TTF-1) are transcription factors that have been recently proposed as IHC markers of intestinal and pulmonary adenocarcinomas, respectively. However, their expression in NETs has not been widely studied. The objective of this study is to evaluate the expression of TTF-1 and CDX-2 in NETs and their potential usefulness in distinguishing gastrointestinal and pulmonary NETs from other sites. We performed an IHC study on formalin-fixed, paraffin-embedded sections from 155 primary NETs, including 60 pulmonary, 60 gastrointestinal, 30 pancreatic, and 5 NETs from other sites. In addition, we evaluated 13 metastatic NETs, including 11 cases of gastrointestinal and 2 of pulmonary origin. In this study, CDX-2 was expressed in 28/60 (47%) of gastrointestinal NETs with the following results: 11/11 (100%) appendiceal, 12/14 (86%) small intestinal, 3/4 (75%) colonic, 2/11 (18%) rectal, and 0/20 (0%) gastric. TTF-1 was expressed in pulmonary carcinoid tumors in 13/30 (43%) and in 27/30 (90%) pulmonary small cell carcinomas. NETs of other origins (pancreas, skin, ovary, and thymus) were negative for both TTF-1 and CDX-2. Metastatic neuroendocrine neoplasms of intestinal origin were positive for CDX-2 and negative for TTF-1. In conclusion, CDX-2 expression is highly specific in identifying NETs of intestinal origin and TTF-1 expression is helpful in identifying NETs of pulmonary origin, which can be quite useful in the diagnosis of metastatic NETs of unknown origin.

Pancreatic neuroendocrine tumours

Pancreatic neuroendocrine tumours (PET) are rare neoplasms of the pancreas accounting for less than 5% of all primary pancreatic malignancies. Included in this group are insulinomas, gastrinomas, glucagonoma and somatostatinomas. Collectively these neoplasms are classified as functional PETs. Where a PET is not associated with a clinical syndrome due to hormone oversecretion, it is referred to as a non-functioning PET. Non-functioning PETs are pancreatic tumours with endocrine differentiation but lack a clinical syndrome of hormone hypersecretion. The incidence of these tumours varied between 15 and 53%. Presentation is related to the mass effect of the tumour with symptoms often non-specific. Treatment is surgical excision with chemotherapy and hormonal therapy is controversial. For functioning PETs, surgery remains the optimal therapy, however, long-term survival can be expected even in the presence of metastases. With advances in medical management, radiolabelled somatostatin therapy, hepatic arterial chemoembolisation and radiofrequency ablation, symptoms may be controlled to optimize quality of life.

Minute mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth

We report a rare case of minute (5 mm x 4 mm) mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth. A 34-year-old Japanese man was admitted because of elevated serum pancreatic enzymes. Endoscopic retrograde pancreatography revealed an unidentified material of 18 mm within the main pancreatic duct. Stone or parasite with acute pancreatitis was suspected clinically, and the biopsy revealed malignant cells positive for CA19-9, carcinoembryonic antigen (CEA) and synaptophysin. No apparent tumor was identified in the pancreas by various imaging techniques. Resection of pancreatic body and tail was performed. Grossly, the main pancreatic duct in the pancreatic body was occluded by as much as 20 mm. The pancreas had minute carcinoma of 5 mm x 4 mm just around the occluded main pancreatic duct. The tumor cells invaded the main pancreatic duct and spread within it as long as 20 mm. Histologically, the carcinoma had biphasic pattern; one was ductal carcinoma with tubular formations and another was carcinoma with neuroendocrine features. These two elements were admixed, and the ductal element comprised 30% while the endocrine element comprised 70%. The ductal element was immunoreactive for cytokeratins, CEA and CA19-9, while the endocrine element was immunoreactive for chromogranin A and synaptophysin. No immunoreactivity for pancreatic enzymes was noted. Ultrastructural observations showed dense core granules and no zymogen granules. Our case is unique clinically in that the tumor manifested as an intraductal material and no apparent tumor was found by imaging modalities, and pathologically in that the tumor was rare mixed ductal-endocrine carcinoma and the tumor was very small and mainly grew within the main pancreatic duct.

Apudomas pancreáticos: um desafio para clínicos e cirurgiões

OBJETIVO: O propósito do presente estudo é analisar as dificuldades quanto ao diagnóstico, avaliação prognóstica e conduta em sete pacientes portadores de tumores neuroendócrinos do pâncreas (apudomas), estudados na última década, comparando os resultados com aqueles discutidos na literatura. MÉTODO: A idade dos pacientes variou de 15 a 66 anos, com média de 38,4 anos. Todos foram submetidos a alguma forma de ressecção pancreática por tumores neuroendócrinos. Os exames histológicos foram feitos pelas técnicas tradicionais e por imuno-histoquímica. RESULTADOS: Três pacientes tiveram um diagnóstico inespecífico de tumor neuroendócrino; dois de vipoma e dois de gastrinoma. As síndromes não se manifestaram claramente, ainda que cada caso tenha tido um rótulo diagnóstico. Os exames por imuno-histoquímica demonstraram a presença de múltiplos hormônios, mas por falta de sintomas clínicos, as correlações ficaram prejudicadas na maioria dos casos, havendo correlação somente em caso de gastrinoma. Um paciente faleceu no pós-operatório; um sobreviveu sete anos e cinco estão vivos, com sobrevida variando entre três e cinco anos. CONCLUSÕES: Não houve uma manifestação sindrômica evidente, porém a sobrevida dos pacientes tem sido compatível com os dados de literatura.

Thyroid transcription factor-1 is expressed in extrapulmonary small cell carcinomas but not in other extrapulmonary neuroendocrine tumors

Thyroid transcription factor-1 (TTF-1) is a nuclear homeodomain transcription factor that is expressed in the developing thyroid, respiratory epithelium, and diencephalon. TTF-1 is thought to be expressed specifically in pulmonary or thyroid neoplasms, and it is expressed in a significant subset of pulmonary non-small cell carcinomas, small cell carcinomas, and carcinoids but not in nonpulmonary, non-small cell carcinomas. Neuroendocrine tumors from sites other than the lung have not been evaluated for TFF-1 expression. We examined TFF-1 expression using immunohistochemistry on formalin-fixed, paraffin-embedded sections of 49 gastrointestinal carcinoids; 15 pancreatic islet cell tumors; 21 paragangliomas; 8 medullary thyroid carcinomas; 7 small cell carcinomas of the uterine cervix; 4 prostate, 4 bladder, and 6 Merkel cell (primary cutaneous neuroendocrine) carcinomas; and 1 renal carcinoma No gastrointestinal carcinoid tumor, pancreatic islet cell tumor, paraganglioma, or Merkel cell carcinoma expressed TFF-1. All of the medullary thyroid carcinomas strongly expressed TTF-1. However, 44% of nonpulmonary small cell carcinomas were also TTF-1 positive, including four of four prostate, two of four bladder, and one of seven cervical small cell carcinomas. We conclude that TTF-1 expression is not specific for small cell carcinomas of pulmonary origin and should not be used to distinguish primary from metastatic small cell carcinomas in extrapulmonary sites. However, TTF-1 expression may be useful in distinguishing Merkel cell carcinomas and cutaneous metastasis of small cell carcinomas. Among well-differentiated neuroendocrine tumors, TTF-1 expression seems to be present only in carcinoid tumors of the lung and medullary carcinomas of the thyroid and may be of differential diagnostic value when dealing with a metastatic well-differentiated neuroendocrine tumor.

Protocol for the examination of specimens from patients with endocrine tumors of the pancreas, including those with mixed endocrine and acinar cell differentiation: a basis for checklists. Cancer Committee of the College of American Pathologists

No Abstract Available

Proliferative Activity in Pancreatic Endocrine Tumors: Association with Function, Metastases, and Survival

Endocrine tumors of the pancreas are slow-growing lesions, yet one-third to one-half will metastasize. It is generally accepted that histopathologic features do not reliably predict metastatic potential or outcome. We investigated whether proliferative activity, as determined by MIB-l labeling, correlated with tumor type, metastasis, or patient survival. Formalin-fixed sections of pancreatic endocrine tumors were immunohistochemically stained for the MIB-l antibody against Ki-67 using the avidin-biotin complex technique. Labeling index (LI) was determined by counting 1000 consecutive tumor cells in an area of greatest staining intensity at x400 and expressed as a percentage. The study group included 37 patients, including 10 gastrinomas, 9 insulinomas, 4 glucagonomas, 2 VlPomas, and 12 nonfunctioning tumors. Twenty-one patients had metastases, primarily to regional lymph nodes and the liver. Five patients had MEN I. MIB-1 LI was significantly greater in the nonfunctioning tumors (mean 20S%) than in the functioning tumors (mean 51%) (p = 0.01). LI for functional tumors (insulinomas 64%, glucagonoma 44%, gastrinomas 32%, VlPomas 32%) were similar to each other, MIB-1 was significantly higher in those tumors that metastasized (mean 15.6%) compared to those that did not (mean 31%), (p = 0.04). All tumors with MIB-1 LI >10% developed metastases. Logistic regression showed that MIB-1 was a significant predictor of metastases (p = 0.003) after adjusting for functional status. MIB-1 LI also correlated with outcome in that those patients with MIB-1 LI >/=10% had a mean survival of 19 mo compared to 72 mo for those with levels <10% (p = 0.0001). Results of the proportional hazards model showed that MIR-1 remained a significant (p = 0.03) and independent predictor of survival times after adjustment for tumor size and functional status. Higher MIB-1 LI values were significantly associated with shorter survival times. In conclusion, MIB-1 LI appears to be a useful indicator of metastatic potential and is predictive of outcome in PET.

Pancreatic development and maturation of the islet B cell. Studies of pluripotent islet cultures

Pancreas organogenesis is a highly regulated process, in which two anlage evaginate from the primitive gut. They later fuse, and, under the influence of the surrounding mesenchyme, the mature organ develops, being mainly composed of ductal, exocrine and endocrine compartments. Early buds are characterized by a branching morphogenesis of the ductal epithelium from which endocrine and exocrine precursor cells bud to eventually form the two other compartments. The three compartments are thought to be of common endodermal origin; in contrast to earlier hypotheses, which suggested that the endocrine compartment was of neuroectodermal origin. It is thus generally believed that the pancreatic endocrine-lineage possesses the ability to mature along a differentiation pathway that shares many characteristics with those of neuronal differentiation. During recent years, studies of insulin-gene regulation and, in particular, the tissue-specific transcriptional control of insulin-gene activity have provided information on pancreas development in general. The present review summarizes these findings, with a special focus on our own studies on pluripotent endocrine cultures of rat pancreas.

Prognostic criteria in nonfunctioning pancreatic endocrine tumours

To identify prognostic subgroups among non-functioning (nonsyndromic) pancreatic endocrine tumours, a series of 61 tumours were analysed systematically for macroscopic, histopathological and immunohistochemical variables potentially predictive of malignancy. High-grade nuclear atypia, elevated mitotic rate and multifocal necrosis allowed us to separate 5 poorly differentiated carcinomas from 56 well differentiated tumours. Among the latter, 29 well-differentiated carcinomas showing gross local invasion or metastases were identified. Vascular or perineural microinvasion, Ki67 proliferative index > 2%, mitotic rate > or = 2, size > or = 4 cm, capsular penetration, nuclear atypia, lack of progesterone receptors and presence of calcitonin were among the variables correlated with malignancy. The first two were the most sensitive and specific. Their presence or absence was used in the 27 tumours lacking evidence of malignancy at the time of surgery to separate 11 cases with increased risk of malignancy (in 2 of which metastases developed during follow-up) from 16 cases with limited risk. The resulting four prognostic groups of non-functioning pancreatic endocrine tumours (limited- and increased-risk tumours, well-differentiated carcinomas and poorly differentiated carcinomas) showed distinct survival curves, which were significantly affected by vascular microinvasion, Ki67 proliferative index and metastases.

Clinical spectrum of hyperglucagonemia associated with malignant neuroendocrine tumors

OBJECTIVE

To review the clinical features associated with hyperglucagonemia in malignant neuroendocrine tumors.

MATERIAL AND METHODS

We retrospectively reviewed the medical records of patients with hyperglucagonemia encountered at our institution from Oct. 17, 1988, through February 1993 who had a fasting serum glucagon level of at least 120 pg/mL (twice the normal value). The 71 study patients also had no evidence of a secondary cause of hyperglucagonemia and had pathologic confirmation of a neuroendocrine tumor.

RESULTS

The study group consisted of 46 men and 25 women with a median age of 57 years. Two patients had multiple endocrine neoplasia. Forty-nine patients had biochemically polyfunctional tumors, and 22 had hyperglucagonemia only. The most common initial symptoms were weight loss, abdominal pain, diarrhea, nausea, peptic ulcer disease, diabetes, and necrolytic migratory erythema (NME). Diabetes eventually developed in 25 patients and was associated with NME in 11. The highest median serum glucagon values occurred in patients with the glucagonoma syndrome or insulinomas, and the lowest median values were in those with carcinoid syndrome, Zollinger-Ellison syndrome, or diabetes without NME. Fasting glucagon and glucose measurements were not correlated. The most common hormonal syndromes were the Zollinger-Ellison syndrome and the glucagonoma syndrome. All the neuroendocrine tumors were malignant. Several methods of treatment, including surgical debulking, chemotherapy, somatostatin, and hepatic artery embolization, were used. Death occurred in 29 patients at a median of 2.79 years after diagnosis; 42 patients were alive at a median of 2.86 years after diagnosis.

CONCLUSION

A mild degree of hyperglucagonemia can commonly be associated with multifunctional neuroendocrine tumors. The glucagonoma syndrome occurs in a few patients with malignant neuroendocrine tumors and hyperglucagonemia and is associated with very high serum glucagon levels. The correlation between serum glucagon levels and the development of diabetes is limited, and other factors such as insulin may be more important than hyperglucagonemia in the development of diabetes.

A pancreatic endocrine tumor arising within a serous cystadenoma of the pancreas

We report a pancreatic endocrine tumor arising within an otherwise benign pancreatic serous cystadenoma in a 47-year-old woman with a history of lupus treated by steroids. She presented 10 years before resection with epigastric pain and intermittent jaundice. Histologic and immunohistochemical studies showed that the solid endocrine component was composed of small, uniform cells with stippled nuclei, which were chromogranin A positive. The surrounding cystic component was lined by periodic acid Schiff's-positive, diastase-digestible cells containing glycogen. To the best of our knowledge, this is the first case of a serous cystadenoma of the pancreas that contains a well defined pancreatic endocrine tumor reported in the English literature.

The glucagonoma syndrome. Clinical and pathologic features in 21 patients

The glucagonoma syndrome is a rare disorder characterized by weight loss, necrolytic migratory erythema (NME), diabetes, stomatitis, and diarrhea. We identified 21 patients with the glucagonoma syndrome evaluated at the Mayo Clinic from 1975 to 1991. Although NME and diabetes help identify patients with glucagonomas, other manifestations of malignant disease often lead to the diagnosis. If the diagnosis is made after the tumor is metastatic, the potential for cure is limited. The most common presenting symptoms of the glucagonoma syndrome were weight loss (71%), NME (67%), diabetes mellitus (38%), cheilosis or stomatitis (29%), and diarrhea (29%). Although only 8 of the 21 patients had diabetes at presentation, diabetes eventually developed in 16 patients, 75% of whom required insulin therapy. Symptoms other than NME or diabetes mellitus led to the diagnosis of an islet cell tumor in 7 patients. The combination of NME and diabetes mellitus led to a more rapid diagnosis (7 months) than either symptom alone (4 years). Ten patients had diabetes mellitus before the onset of NME. No patients had NME clearly preceding diabetes mellitus. Increased levels of secondary hormones, such as gastrin (4 patients), vasoactive intestinal peptide (1 patient), serotonin (5 patients), insulin (6 patients, clinically significant in 1 only), human pancreatic polypeptide (2 patients), calcitonin (2 patients) and adrenocorticotropic hormone (2 patients), contributed to clinical symptoms leading to the diagnosis of an islet cell tumor before the onset of the full glucagonoma syndrome in 2 patients. All patients had metastatic disease at presentation. Surgical debulking, chemotherapy, somatostatin, and hepatic artery embolization offered palliation of NME, diabetes, weight loss, and diarrhea. Despite the malignant potential of the glucagonomas, only 9 of 21 patients had tumor-related deaths, occurring an average of 4.91 years after diagnosis. Twelve patients were still alive, with an average age follow-up of 3.67 years.

Tumors of the endocrine/neuroendocrine system: an overview

For the sake of discussion, the markedly diversified tumors of the endocrine/neuroendocrine system are classified as those originating in classic epithelial endocrine organs (eg, adrenal cortical adenomas), from the diffuse endocrine cells (eg, jejunal carcinoid tumors), or from clusters of these cells (eg, islet cell tumors); and those arising from neurosecretory neurons (eg, neuroblastoma) or paraganglia (eg, carotid body tumor). Although traditional transmission electron microscopy is useful for identifying neurosecretory or endosecretory granules as such, with few exceptions (eg, insulin-containing granules with a complex paracrystalline core) it is not possible to ascribe a granule type (size, shape, or ultrastructure) to a distinct nosologic entity or secretory product because of their overlapping fine structures in different cell types. Immunoelectron microscopy methods utilizing colloidal gold-labeled secondary antibodies can be used to localize virtually any antigen (peptide or neuroamine) to a specific neurosecretory or endosecretory granule or other cell structure. General endocrine/neuroendocrine cell markers such as neuron-specific enolase, the chromogranins, and synaptophysin are useful in identifying neuroendocrine differentiation in a neoplasm using routine immunohistochemical procedures. The current relevance of the APUD concept of Pearse as well as the biologic importance of endocrine/neuroendocrine secretory products such as bombesin and insulinlike growth factors also are discussed.

Diagnostic advances in APUDomas and other endocrine tumors: imaging and localization

The different diagnostic imaging modalities available for determining the location of the various APUDomas are discussed with reference to their advantages and disadvantages. The ability to image these lesions, and to be confident in their role in the underlying pathophysiology, and clinical neuroendocrine syndrome causing symptomatology and illness, has proved to be the key to successful treatment. In many instances it is not the diagnosis that is in question, but it is the extent of disease, the location of the lesion, or whether the anatomical abnormality under study is responsible for the complicating symptoms being considered, that are the crucial questions. The ability to locate APUDomas by a variety of direct and indirect imaging or regionalizing modalities, represent a magnificent advance in the management of these tumors. It should, however, be kept in mind that no one modality or diagnostic method can uniformly be relied upon. It is evident that a multimodal, interactive medical team approach is essential to the successful overall management of patients afflicted with these fascinating tumors.

Malignant mixed exocrine-endocrine tumor of the pancreas with unusual intracytoplasmic inclusions

A case of malignant mixed exocrine-endocrine tumor of the pancreas is reported. Electron microscopy revealed abundant neurosecretory granules in most cels. Zymogen granules indicating acinar differentiation were seen in a few cells. Ductal features, including microvilli with prominent filamentous cores and intracytoplasmic mucin granules, were also noted in this lesion. immunocytochemical strains were positive for serotonin and glucagon. Unusual intracytoplasmic fibrillary inclusions are described and their possible origin discussed.

The endocrine pancreas and its tumors

The endocrine pancreas is a complex and important gland that is essential for fuel metabolism. Morphological investigations have an important role in the study of the normal and pathological endocrine pancreas. Endocrine tumors of the pancreas represent a group of hormone-producing neoplasms that can give rise to a variety of clinical manifestations. Their cytodifferentiation and hormonal activity can be determined using a number of sophisticated morphological techniques, including immunohistochemistry, electron microscopy, and ultrastructural immunocytology. In some cases, tissue culture has a role in the analysis of their hormonal profile. Recent advances in molecular biology have paved the way for studies of the factors that underlie cytodifferentiation and pathogenesis of these lesions. Transcription factors may determine hormonal activity and differentiation of cell types in the endocrine pancreas, and transgenic mouse models have shed light on the development of endocrine tumors in the pancreas.Endocr Pathol 4:120-130, 1993.

The midgestational human fetal pancreas contains cells coexpressing islet hormones

In the fetal development of the mouse pancreas, endocrine cells have been found that express more than one hormone simultaneously. Our objective was to evaluate the existence of such cells in the human fetal pancreas. We found cells coexpressing two of the major pancreatic hormones (insulin, glucagon, and somatostatin) in sections of eight midgestational (12-18 weeks) pancreata and in 0-7% of cells in single-cell suspensions from midgestational pancreata. By electron microscopy, using granule morphology and immunoelectron microscopic techniques, we could confirm these findings and even detect cells containing three hormones. Morphologically different granules contained different immunoreactivities, suggesting parallel regulation of hormone production and packaging. In six newborn pancreata (born after 22-40 weeks of gestation), we could not find any multiple-hormone-containing cells. Subsequently, we evaluated whether multiple-hormone-containing cells proliferate by using pancreatic fragments and single-cell preparations at the light and electron microscopic level (six pancreata). No endocrine hormone-containing cells incorporated bromodeoxyuridine during a 1-hr culture period, indicating that these cells have lost the ability to proliferate under the conditions chosen. We conclude that, as in mice, the human fetal pancreas of 12-18 weeks of gestation contains endocrine cells that express multiple hormones simultaneously. These (multiple) hormone-containing cells do not seem to proliferate under basal conditions.

Colocalization of pancreatic polypeptide and insulin in secretory granules of a pancreatic endocrine neoplasm

A 45-year-old woman presented with clinical symptoms of hypoglycemia of 4 months duration. Laboratory testing confirmed hyperinsulinemia; mild hypercalcemia and hypergastrine-mia were also documented. At the time of operation, 3 pancreatic endocrine neoplasms were found, and a diagnosis of multiple endocrine neoplasia type I was made. Immunohistochem-istry and immunoelectron microscopy showed all the tumors to be plurihormonal, each containing three or more of the following: insulin, glucagon, somatostatin, pancreatic polypep-tide, gastrin, and serotonin. Electron microscopy of 2 tumors revealed numerous atypical granules. In 1 tumor, pancreatic polypeptide and insulin were colocalized in secretory granules by dual-staining immunoelectron microscopy. To our knowledge, this combination of hormones has not been described previously in pancreatic endocrine neoplasms and suggests that such neoplasms, like mature pancreatic endocrine cells, may originate from pluripotential common precursor cells.

Hepatoblastomas: an ultrastructural and immunohistochemical study

Seven hepatoblastomas were studied by electron microscopy, and four of these were studied by immunohistochemistry. Five tumors were purely epithelial, and two were mixed epithelial-mesenchymal. They showed a spectrum of cellular differentiation ranging from primitive epithelial cells to differentiated cells resembling adult hepatocytes. Glycogen, lipid, basal lamina, and canaliculi were present in all cases. Mitochondria with large, membrane-bound, amorphous inclusions were present in one tumor, and large, complex, basal cell processes were present in two tumors. Ultrastructural features most characteristic of hepatocytes were most common in fetal type hepatoblastomas. Immunoreactive chromogranin cells were present in two tumors, one of which also contained immunoreactive somatostatin cells. The somatostatin-positive tumor had cells with granules resembling those seen in somatostatin-containing cells of normal pancreas and somatostatin-containing neuroendocrine carcinomas. Other immunoreactive substances were present, including alpha 1-antitrypsin (four cases), vimentin (embryonal cells in four cases; fetal cells in three cases), low-molecular weight cytokeratin (embryonal cells in three cases; fetal cells in four cases), and high-molecular weight cytokeratin (embryonal cells in one case; fetal cells in two cases). Osteoidlike material was positive for epithelial membrane antigen, vimentin, and S-100 protein.

The contribution of ultrasonography and computed tomography in the diagnosis of nonfunctioning islet cell tumors of the pancreas

The personal series of 12 nonfunctioning islet cell tumors (NFIT) of the pancreas is reported. The ultrasound and computed tomography features of NFIT are analyzed, and a few signs are identified that may be useful in the differential diagnosis vs ductal carcinoma. The necessity to complete the diagnostic work up by means of fine needle aspiration biopsy and cytologic smears is also emphasized.

Classification and histogenesis of gastroenteropancreatic endocrine tumours

A series of 267 gastroenteropancreatic endocrine tumours has been revised from the point of view of histopathologic diagnosis, hormonal profile and clinical behaviour. Results of this investigation, together with revised concepts on the histogenesis of gastroenteropancreatic endocrine growths, allowed to develop detailed classification systems which proved useful for precise tumour diagnosis and for clinicopathologic correlation, with special reference to tumour function, prognosis and therapy. Among 132 pancreatic growths, various types of islet cell tumours (61 cases), with (45 cases) or without (16 cases) hyperfunctional syndrome, were separated from different types of gut-related (38 cases) and 'ectopic' (three cases) tumours, as well as from 25 non-functioning, locally symptomatic tumours, three small cell carcinomas and two mixed endocrine-exocrine tumours. Among 97 intestinal tumours, 39 argentaffin EC cell carcinoids, mostly from the appendix and ileum, were separated from 23 hindgut-type carcinoids, mostly from the rectum, 22 gastrin cell tumours, mainly from the duodenal bulb, five somatostatin cell tumours, mostly from the periampullary region of the duodenum, and two gangliocytic paragangliomas. Among 38 gastric tumours, five small cell 'neuroendocrine' carcinomas were separated from three gastrin cell tumours and 30 argyrophil carcinoids, 27 of which arose in the body fundus, 16 associated with chronic atrophic gastritis and four with combined Zollinger Ellison/Multiple Endocrine Neoplasia Syndrome.

Hepatic arterial embolization for metastatic hormone-secreting tumors. Technique, effectiveness, and complications

Ten patients with hepatic metastases from islet cell tumors or carcinoid tumors had clinical symptoms from hormonal secretion and/or pain related to the mass effect of neoplastic liver involvement. Hepatic arterial embolization (HAE) using radiographically guided catheters to inject thrombogenic material was applied to the right and/or left hepatic arteries separately 5 to 7 days apart. All ten patients improved within days of the procedure as confirmed by a decrease in measurable hormone levels (gastrin, adrenocorticotropin, and 5-hydroxy indole acetic acid) or by a decrease in tumor size and improved symptoms. Three patients underwent repeated reembolization from two to four times over nine to 50-month intervals for symptom control. Complications of and indications for HAE in these patients are discussed. It appears to be an effective treatment for dealing with the hormonal syndromes and local symptoms related to the hepatic metastases of hormone-secreting tumors.

Mechanism for increase of gastrin release by secretin in Zollinger-Ellison syndrome

In patients with Zollinger-Ellison syndrome, serum gastrin level is increased by secretin and is decreased by somatostatin. To elucidate the cellular mechanism for these actions, we investigated the direct effects of secretin and somatostatin on dispersed gastrinoma cells from a patient with Zollinger-Ellison syndrome. In the presence of 3-isobutyl-1-methylxanthine, secretin significantly stimulated gastrin release from dispersed gastrinoma cells, which was inhibited by somatostatin. In the presence of guanosine 5'-triphosphate, furthermore, secretin enhanced adenylate cyclase activation in the membranes from these cells, and this activation was reduced by somatostatin, whereas neither secretin nor somatostatin affected inositol phospholipid turnover. On the other hand, removal of guanosine 5'-triphosphate from incubation medium abolished both the stimulatory effect of secretin and the inhibitory effect of somatostatin on adenylate cyclase activation. Furthermore, pertussis toxin pretreatment reversed the ability of somatostatin to inhibit secretin-induced increase in gastrin release and activation of adenylate cyclase. Thus, in this gastrinoma patient, secretin and somatostatin appeared to act directly on gastrinoma cells to stimulate and inhibit gastrin secretion, respectively, by modulating adenylate cyclase activation, probably via guanine nucleotide-binding proteins.

Histogenesis of neoformation in the endocrine pancreas of aging horses

Pancreatic tissue from 20 horses was examined using immunocytochemical techniques. In aged horses, neogenesis of endocrine cells, neoformation, and hyperplasia of islets occurred closely associated with the pancreatic duct; these changes were regarded as nesidioblastosis. In addition, pancreatic fibrosis accompanied by ductal proliferation and endocrine neogenesis was considered a regenerative change. Thus, the origin of neoformation in the endocrine pancreas was in the ductal system, and it is suggested that the pancreatic endocrine cells were of endodermal origin.

Argyrophilic and hormone immunoreactive cells in normal and hyperplastic pancreatic ducts and exocrine pancreatic carcinoma

Scattered argyrophil cells were present in normal, large, medium-sized and small pancreatic ducts (ductules). There was marked increase in argyrophil cells in ducts with hyperplastic epithelium. Argyrophil cells were also found in 67.7% of all exocrine pancreatic carcinomas. In a well differentiated group including cystadenocarcinoma, mucinous carcinoma and well differentiated ductal adenocarcinoma argyrophil cells were found in all cases examined. Using four antisera (against insulin, glucagon, somatostatin and gastrin), insulin, glucagon and somatostatin cells were identified in 2.65%, 0.001% and 1.2% of normal ducts, and 7.5%, 2.4% and 4.6% of ducts with hyperplastic epithelium respectively and were also greatly increased in numbers in the latter group. Immunoreactive cells were present in 66.7% of exocrine carcinomas. Cells reactive for insulin were found in 7/15 cases; glucagon in 6/15 cases; somatostatin in 5/15 cases and gastrin in 2/15 cases. Eight cases contained two or more than two types of immunoreactive cells. The presence of argyrophil and hormone immunoreactive cells in pancreatic ducts and carcinomas is indicative of the close developmental relationship between endocrine and exocrine parts of the pancreas. The inter-relationship of response in the different cell types following stimulus suggests that injury to a common precursor may be involved.

Cloned cell lines from a transplantable islet cell tumor are heterogeneous and express cholecystokinin in addition to islet hormones

A liver metastasis (MSL) with a remarkable in vitro proliferation potential has been identified in an NEDH rat carrying a transplantable x-ray-induced islet cell tumor. Two insulin-secreting cell lines, MSL-G and MSL-H, with doubling times of 3-5 d were established by repeated limiting dilution cloning. In vivo inoculation of MSL-G cells induced severe hypoglycemia caused by a small but highly heterogeneous tumor as revealed by immunocytochemistry. Whereas most cells stained for the islet hormones, insulin, glucagon, and somatostatin, clustered cells were discovered to contain cholecystokinin (CCK). Additional in vitro-limiting dilution cloning, followed by immunocytochemical characterization, clearly demonstrated the capacity of single cell clones to simultaneously express the same four hormones. Radioimmunoassays with a panel of site-specific antisera of culture supernatants and purified cell extracts showed the MSL-G2 cells to produce, store, and secrete readily detectable amounts of processed and unprocessed CCK. Gastrin was not detected while coexpression of glucagon and CCK were demonstrated. Mutant clones selected for resistance to 6-thioguanine (frequency, 2 X 10(-7] and checked for HAT (hypoxanthine, aminopterin, thymidine) sensitivity retained the capacity for multi-hormone expression. We propose that the MSL tumor contains pluripotent endocrine stem cells. The MSL tumor and the MSL-G2 cells in particular will allow studies of not only CCK biosynthesis and processing but also of mechanisms involved in tumor and islet cell differentiation.

Secretory granules in benign and malignant glucagonomas of the pancreas

Two cases of glucagonoma, one benign and the other malignant, was presented. Benign glucagonoma in a 29-year-old man with multiple endocrine neoplasia type 1 was composed largely of tumor cells with secretory granules ranging from 139 to 417 nm in diameter identical to A cell granules. There were a few tumor cells which contained no A cell granules but smaller granules of approximately 166 nm diameter similar to those of pancreatic polypeptide containing cells. Radioimmunoassay of the tumor extract showed 319 micrograms/g wet weight of glucagon and 0.72 microgram/g wet weight of pancreatic polypeptide. Malignant glucagonoma in a 34-year-old man was a massive tumor of 7 X 6 X 5 cm replacing the tail and body of the pancreas with multiple metastases. The tumor contained 0.2 microgram/g wet weight of glucagon and 0.065 microgram/g wet weight of vasoactive intestinal peptide. The electron microscopic examination revealed that the tumor cells had variable numbers of atypical secretory granules measuring 110 to 200 nm in diameter different from A cell granules. An analysis of plasma glucagon by the gel filtration technique showed the heterogeneity of glucagon molecules indicating the presence of large glucagon. Atypical secretory granules in malignant glucagonoma were considered to represent immature granules containing the precursor or intermediate of glucagon.

Tumors of the diffuse endocrine system, histochemical and electron-optic aids, and pitfalls in diagnosis

Tumors of the Diffuse Endocrine System are a heterogeneous group of malignant neoplasms which have rather characteristic light microscopic and cytologic features. These are, however, not diagnostic and their identification with separation from non-neuroendocrine carcinomas require important adjunctive evaluations including histochemical analysis, immunocytochemical characterization and electron-optic identification of endocrine secretory products and paracrine effects in the cytoplasm of the neoplastic cells. The importance of proper classification cannot be over-emphasized because of the often considerable biologic and prognostic differences between neuroendocrine carcinomas and other types of carcinoma, notably metastatic carcinomas from the breast and the prostate. Furthermore, the separation of these lesions into two groups; a small cell type and those with large cells (carcinoid type) appears to have clinical significance in both diagnosis and response to therapy.

Recurrent insulinoma syndrome with metastatic glucagonoma

A case is reported of a patient who presented with symptomatic hypoglycaemia and who had three pancreatic tumours resected over the ensuing eight years. Immunocytochemistry demonstrated two of these to be insulinomas and the third to be a glucagonoma. In addition metastatic spread of cells positive for glucagon had occurred to a lymph node and multiple nodules staining positively for glucagon were present in the remainder of the pancreas.

Immunoreactive somatostatin and vasoactive intestinal polypeptide in adrenal pheochromocytoma. An immunochemical and ultrastructural study

An adrenal pheochromocytoma producing somatostatin (SRIF) and vasoactive intestinal polypeptide (VIP) in a 17-year-old boy is presented. High concentrations of immunoreactive (IR)-SRIF were found in plasma taken from the antecubital vein (31.0-33.0 pg/ml) and the inferior caval vein near the tumor (54.6 pg/ml), but after removal of the tumor the values became normal (11.0-15.2 pg/ml). In two portions of the resected tumor, considerable but different amounts of IR-SRIF (151.7 and 12.1 ng/g wet wt) and IR-VIP (13.0 and 5.5 ng/g wet wt) were demonstrated with size heterogeneities. Immunohistochemically, many IR-SRIF cells and a few IR-VIP cells were observed, but no cell reacting with both anti-SRIF and anti-VIP sera was found. Electronmicroscopically, many tumor cells had catecholamine-like granules (250-350 nm in diameter) while some others had VIP-like granules (110-140 nm in diameter). However, no granules resembling the SRIF granules seen in the pancreatic D cells were found. This seems to be the first report of an adrenal pheochromocytoma that produces SRIF and VIP simultaneously. It provides information on the histogenesis of hormone-producing neurogenic tumors.

Glucagonomas. Ultrastructure and immunocytochemistry

Pancreatic tumors harboring glucagon immunoreactive cells were found in four patients with diabetes mellitus. Alpha-cell (glucagon) granules were present in three tumors; pancreatic polypeptide (PP) immunoreactive cells were detected in two. In two patients the tumors were malignant and one of these had the glucagonoma syndrome; the other was a member of a family with MEN-type I syndrome. These cases illustrate three clinical subtypes of glucagonoma.

Polypeptide YY (PYY) and pancreatic polypeptide (PP) in rectal carcinoids. An immunocytochemical study

The frequency and distribution of polypeptide YY (PYY) and pancreatic polypeptide (PP) immunoreactive tumour cells of 14 small intestinal and of 27 rectal carcinoids were studied. All small intestinal and 14 rectal tumours were unreactive to both hormones. However, 13 rectal carcinoids contained a variable number of PP-immunoreactive cells. In four of these cases both PYY- and PP-immunoreactive cells were seen. The PP-immunoreactive cells greatly exceeded the number of PYY-immunoreactive cells. Two rectal carcinoids with PYY and PP immunoreactivities, but not the rest of the tumours, reacted also with an antiserum specific to the C-terminus of PP. This indicates that most PP immunoreactive rectal carcinoids lack the C-terminus sequence of the PP molecule.

Gastrin release from gastrinoma cells stimulated with secretin

The secretin injection test has been proved to be useful in the diagnosis of gastrinoma in vivo. Fresh gastrinoma cells were cultured for a short time in vitro and then stimulated with secretin. A rise in the gastrin concentration in the culture medium was observed within 10 min after the addition of secretin. This fact may be evidence that gastrinoma cells have receptors which bind with secretin resulting in the release of gastrin.

Apparent suicide by carbon monoxide poisoning in a case of insulinoma

A woman, found dead in her garage, had a fatal level of carboxyhaemoglobin in her blood. Her recent medical history tended to support a suspicion of suicide but at autopsy a small islet cell tumour was discovered in her pancreas. Further investigations indicated that she had a high blood insulin level, sufficient to produce lethargy or coma, at the time of death. In the light of these findings it was concluded that her death was accidental. The techniques available for investigating the significance of islet cell tumours found at post-mortem are discussed.

[The endocrine cells of the digestive system (author's transl)]

Endocrine cells occur in the digestive system as micro-organs (islets of Langerhans) or scattered throughout the epithelium of the gastrointestinal tract ("diffuse endocrine epithelial organ" of Feyrter). These gastro-entero-pancreatic (GEP) endocrine cells synthesize--in addition to serotonin--a great variety of polypeptide hormones, which regulate both carbohydrate metabolism and digestive processes. The present review deals mainly with cytology and cytochemistry of GEP endocrine cells. A synopsis is presented of the 19 endocrine cell types identified to date, which includes their update nomenclature and their anatomical distribution pattern. Morphological-functional aspects of cell biology, pathology, and cytogenesis of theses cells and their position within superimposed systems (APUD cells, paraneurons) are discussed.

Pancreatic endocrine tumors

One hundred twenty-five pancreatic endocrine tumors were analyzed by immunocytochemistry using various antisera. Twenty-three of 27 insulinomas, 10 of 10 PP-omas (PP: pancreatic polypeptide) and 15 of 30 "nonsecreting" tumors were benign, whereas 8 of 13 glucagonomas, 16 of 24 gastrinomas, and 16 of 21 VIP-omas (VIP: vasoactive intestinal polypeptide) were malignant. As a rule, the hormone secreted by the tumor and causing clinical symptoms could be localized by immunocytochemistry. Fifty of 95 active tumors were found to contain cells immunoreactive to peptide(s) not causing clinical symptoms, and 54 of 30 "nonsecreting" tumors were shown to be multicellular. By electron microscopy more than one cell type could be identified in 12 tumors. Histologically, the growth pattern of the tumors was very variable and distribution of immunoreactive cells was distinctly patchy. Radioimmunoassay on extracts of 20 of 27 tumors confirmed the presence of peptides visualized by immunocytochemistry. In 17 of 22 specimens, groups of endocrine cells in close contact with ductules were found in the pancreatic parenchyma distant from the tumor. Pancreatic endocrine tumors probably arise from the pancreatic ductular epithelium. They are often multicellular, producing and sometimes secreting more than one hormone or hormone-like substance. They represent highly complex biologic systems in which the interrelationship of various gastrointestinal-pancreatic hormones can be studied.

Ductuloinsular tumors of the pancreas: a light, electron microscopic and immunohistochemical study

Most pancreatic tumors are of a single cell type and are identified delta as duct, acinar, or islet cell neoplasms. The authors report on three examples with both duct and endocrine characteristics as seen by light microscopy; two with further confirmation of endocrine differentiation by electron microscopy; and one by immunocytochemistry. Mixed differentiation of this sort can be understood by reference to the embryonic pancreas, which develops from the small intestine and forms ducts, intercalated ducts, acini, and islets, with their different cell types. The merging and intermingling of different cell prevents the identification of one specific cell of origin. It also suggests that the neoplastic process here may not be a clonal proliferation from a single cell mutation as this is generally understood. Alternative explanations are briefly mentioned.