Multiple endocrine neoplasia type 1 with multiple leiomyomas linked to a novel mutation in the MEN1 gene

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominantly inherited syndrome. MEN1 is characterized by the presence of functioning and nonfunctioning tumors or hyperplasia of the pituitary gland, parathyroid glands, and pancreatic islet cells. In addition, MEN1 carriers can have adrenal or thyroid tumors and non-endocrine tumors, such as lipomas, angiofibromas, and leiomyomas. Although leiomyoma is not a major component of MEN1, it is thought to occur more frequently than expected. However, there has been no report of a case of MEN1 with leiomyoma in Korea so far. This report describes a patient with multiple leiomyomas in MEN1. A 50-year-old woman was referred for further evaluation of elevated calcium levels and osteoporosis. Biochemical abnormalities included hypercalcemia with elevated parathyroid hormone. There was hyperprolactinemia with pituitary microadenoma in sella MRI. An abdominal MRI demonstrated adrenal nodules and leiomyomas in the bladder and uterus. Endoscopic ultrasonography demonstrated esophageal leiomyoma and pancreatic islet cell tumor. A subtotal parathyroidectomy with thymectomy was performed. Sequencing of the MEN1 gene in this patient revealed a novel missense mutation (D350V, exon 7). This is the first case of MEN1 accompanied with multiple leiomyomas, parathyroid adenoma, pituitary adenoma, pancreatic tumor, and adrenal tumor.     

Varying expression of cytokeratin and neurofilaments in neuroendocrine tumors of human gastrointestinal tract

Twelve cases of gastrointestinal neuroendocrine tumors, including eight carcinoids and four pancreatic islet cell tumors or their metastases, were immunohistochemically analyzed for the expression of different types of intermediate filament proteins. All of the tumors showed cytokeratin positivity in immunostaining, and the Western blotting technique revealed 45- and 52-kilodalton cytokeratins in carcinoid tumors. Three of the islet cell tumors, but none of the carcinoid tumors, showed, in addition, varying numbers of neurofilament-positive tumor cells when evaluated with rabbit and mouse monoclonal antineurofilament antibodies. The presence of only the 70-kilodalton neurofilament and cytokeratin polypeptides in an islet cell tumor was revealed also by using the Western blotting technique. On the other hand, both fetal and adult pancreatic islet cells showed only cytokeratin positivity. Neurofilament-positive epithelial cells were not found in normal small intestines either. The results show epithelial characteristics in normal gastrointestinal neuroendocrine cells and neuroendocrine tumors by their expression of cytokeratin. In addition, some islet cell tumors display the 70-kilodalton neurofilament protein which suggests the acquisition of a new type of intermediate filament during the neoplastic change.     

胰岛肿瘤及胰岛增生的免疫组化研究

应用免疫组化ＡＢＣ及ＬＳＡＢ法，对２７例胰岛肿瘤和３例胰岛增生进行Ｉｎｓ，Ｇａｓ，Ｇｌｕ，Ｓｏｍ，Ｓｅｒ，ＶＩＰ，ＰＰ，ＮＳＥ，ＣＨＧ，ＳＹＰ，ｈＣＧ，ＥＭＡ，Ｋ及ＣＫ的研究。结果显示：胰岛素瘤及胰岛增生Ｉｎｓ均阳性，Ｉｎｓ阳性程度与临床症状的轻重无关。胰岛素肿瘤多数为混合性的，而增生基本上是单一的，免疫反应强度与细胞分化程度有关，而与组织学类型无关；无功能性肿瘤仅表现个别激素的弱阳性。ＮＳＥ，ＣＨＧ及ＳＹＰ均是胰岛肿瘤的良好标记，它们与ＥＭＡ及Ｋ（ＣＫ）联合使用，有助于胰岛内分泌肿瘤与外分泌肿瘤的鉴别；ｈＣＧ有助于鉴别胰岛素肿瘤的良恶性。     

Multiple tumors after androgen therapy.

A case of multiple small well-differentiated hepatomas with early peliosis hepatis, multiple pancreatic islet cell tumors, and a renal medullary interstitial cell tumor following five years of androgen and prednisone therapy for idiopathic aplastic anemia is reported in a patient who died shortly after allogeneic bone marrow transplantation. The hepatic tumors were well differentiated, and the pancreatic tumors were of mixed ribbon and islet cell pattern. Therapeutic and experimental implications and the relevant literature are briefly summarized.     

Nesidioblastosis and endocrine hyperplasia of the pancreas: a secondary phenomenon

Diffuse endocrine cell proliferation (nesidioblastosis) and islet cell hyperplasia are considered causes of organic hyperinsulinism but have not been distinguished (by histometric or immunohistologic methods) from the normally variable pancreatic islet cell population during development and in adults. Therefore, in this study morphologic, immunohistologic (to detect insulin, glucagon, somatostatin, and pancreatic polypeptide), and morphometric features were evaluated in 1) normal pancreases (from fetal to adult; n = 49); 2) pancreases from patients with nesidioblastosis (n = 5); and 3) tumor-associated pancreases (TAP) from patients with insulin-producing islet cell tumors (n = 8). The study of normal postnatal development revealed that all features of fetal development remain present after birth and that the diagnosis of any diffuse endocrine disorder should therefore be based essentially on quantitative histometric parameters (total endocrine area, islet size distribution, distribution of each endocrine cell type). With these parameters endocrine cell hyperplasia was demonstrated in TAP from adults due to increased numbers of A and D cells. However, in the cases previously diagnosed as pathologic nesidioblastosis, all parameters were within the normal range. Thus, nesidioblastosis does not appear to be a pathologic entity. Careful re-examination of the pancreases, prompted by these data, revealed small islet cell tumors in three of these five cases. It is concluded that the endocrine pancreas can react rapidly, both morphologically and functionally, to changes in hormonal feedback, e.g., islet cell tumors. Therefore, the observation of a diffuse islet cell disorder in a patient with hyperinsulinism should not be considered an indication that an islet cell tumor is not present.     

Serotonin immunoreactivity in pancreatic endocrine neoplasms (carcinoid tumors).

Primary serotonin secreting pancreatic endocrine neoplasms (carcinoid tumors) are extremely rare and may be associated with manifestations of the carcinoid syndrome. Two cases of primary carcinoid tumor of the pancreas with liver metastases showed clinical and biochemical features of the carcinoid syndrome. Both cases demonstrated strong positive immunoreactivity for serotonin within the tumor cells. In an attempt to determine the relationship between pancreatic carcinoid tumors and other pancreatic endocrine neoplasms, immunostains for serotonin were performed on 11 additional islet cell tumors and on non-neoplastic pancreatic tissues. These cases showed serotonin immunoreactivity within islet cell tumors (36%). In addition, focal staining for serotonin was present in non-neoplastic ducts and ductules (88%), acini (22%), and islets of Langerhans (33%). Based on these observations, specific criteria are suggested for the diagnosis of primary pancreatic carcinoid tumor.     

Prognostic Significance of p27, Ki-67, and Topoisomerase lla Expression in Clinically Nonfunctioning Pancreatic Endocrine Tumors

Nonfunctioning islet cell tumors or pancreatic endocrine tumors are the most common type of malignant islet cell tumor. Although previously detected usually at an advanced stage because of mass effect, the early detection rate of small localized disease has been increasing. To date it has been difficult to predict the clinical behavior in localized regional nonfunctioning tumors. To investigate potential markers predicting malignancy and poor prognosis in nonfunctioning pancreatic endocrine tumors, we analyzed the expression of Ki-67, topoisomerase IIα (Topollα), and p27, as well as a variety of clinicopathologic parameters in 76 cases of nonfunctioning islet cell tumors (23 benign cases and 53 malignant cases). Ki-67, Topollα, and p27 labeling indices were significantly different between benign and malignant tumors. Expression of Ki-67, Topollα, and p27 were associated with survival in patients with a malignant tumor in a univariate setting. However, only p27 and Topollα were jointly associated with survival in multivariate analysis. Immunohistochemical staining for p27, Topollα, and Ki-67 can be helpful in the diagnosis of nonfunctioning pancreatic endocrine tumor. Analysis of p27 and Topollα may also have potential utility as prognostic factors for malignant tumors.     

Somatostatin type 2A receptor immunoreactivity in human pancreatic adenocarcinomas

Somatostatin and its analogs have been included in experimental treatment protocols for advanced pancreatic adenocarcinoma based on their known antisecretory and antiproliferative properties. Somatostatin receptor type 2 (sstr2A) mediates antiproliferative actions of somatostatin and has the strongest affinity to the therapeutically used somatostatin analog—octreotide. We investigated localization of sstr2A in 27 pancreatic adenocarcinomas in relation to tumor histological features and neuroendocrine differentiation confirmed by immunoreactivity for chromogranin A (CgA), chromogranin B (CgB), or somatostatin. Immunoreactivity for sstr2A generally coincided with tumor neuroendocrine differentiation demonstrated by staining for CgA and was present on the cell membranes of pancreatic islet cells and endocrine cells occasionally present in the wall of normal pancreatic ducts. Thirteen pancreatic adenocarcinomas contained cells immunoreactive for sstr2A in numbers ranging from occasional single cells, cell clusters, or carcinoma duct segments. In two cases, cells immunoreactive for sstr2A and CgA represented more than 30 and 10% of the total tumor cell population (case 1 and 15, respectively). Case 1 fulfills the diagnostic criteria of mixed ductal endocrine carcinoma. We conclude that immunohistochemical staining for a generic neuroendocrine marker such as CgA would facilitate identification of a subgroup of pancreatic adenocarcinomas expressing sstr2A receptors. Future studies need to evaluate the responsiveness of these tumors to somatostatin analogue treatment.     

Infection of cultured human fetal pancreatic islet cells by rubella virus

A high incidence of insulin-dependent diabetes mellitus (IDDM) has been reported in children and young adults previously afflicted with congenital rubella syndrome (CRS). The authors have studied the effect of rubella virus infection on human pancreatic islet cells in tissue culture. These experiments were performed with the use of both monolayers and free-floating human fetal islets of Langerhans tissue. Levels of production of immunoreactive insulin by islet cells that had been infected by rubella virus were lower than those observed in control cultures, under conditions of high glucose concentration (11.1 mmol/L) in the medium. The presence of rubella viral antigens in human pancreatic beta and non-beta cells was demonstrated by double-label immunofluorescence. These results suggest that rubella virus can infect human pancreatic islet cells and that such infection may lead to significant reductions in levels of secreted insulin.     

Endocrine pancreatic tumors: ultrastructure

Endocrine pancreatic tumors are frequently multicellular and produce several hormones and peptides. A review of the basic concepts of hormone secretion, pancreatic islet cell composition and ultrastructural make-up of tumors is presented. The importance of correlating ultrastructural, immunocytochemical and biochemical studies of these tumors is emphasized.     

MULTIPLE NONFUNCTIONAL PANCREATIC ISLET CELL TUMOR IN MULTIPLE ENDOCRINE NEOPLASIA TYPE I

A case of multiple nonfunctional pancreatic islet cell tumor in multiple endocrine neoplasia type I (MEN I) is reported. The patient was a 41-year-old woman who had a past history of thyroid cancer (papillary carcinoma) and hyperparathyroidism due to parathyroid adenoma. Later, a nonfunctional pituitary tumor and Ave nonfunctional pancreatic tumors were found simultaneously and the patient was finally diagnosed as having MEN I. Following surgical enucleation, the pancreatic tumors were histopathologlcally diagnosed as benign islet cell tumors. One of them (tumor 3) exhibited a solid nodular pattern while the others showed gyriform patterns. They were divided histochemlcally and immunohistochemically into three types: two (tumors 1 and 2) produced a single hormone (glucagon), one (tumor 3) produced five (Insulin, glucagon, somatostatin, gastrin and pancreatic polypeptide) and the remaining two (tumors 4 and 5) produced two (glucagon and pancreatic polypeptide). Electron microscopically, three types of endosecretory granules were found in the tumor cells of tumor 3 but only one type was found in tumor 4. However, in the tumor 4 extract, glucagon, pancreatic polypeptide, C-peptlde, somatostatin, vasoactive intestinal peptide and growth hormone releasing factor were detected by radioimmunoassay. These findings suggest that these pancreatic tumors were both multicellular and multihormonal.     

Multiple nonfunctional pancreatic islet cell tumor in multiple endocrine neoplasia type I. A case report

A case of multiple nonfunctional pancreatic islet cell tumor in multiple endocrine neoplasia type I (MEN I) is reported. The patient was a 41-year-old woman who had a past history of thyroid cancer (papillary carcinoma) and hyperparathyroidism due to parathyroid adenoma. Later, a nonfunctional pituitary tumor and five nonfunctional pancreatic tumors were found simultaneously and the patient was finally diagnosed as having MEN I. Following surgical enucleation, the pancreatic tumors were histopathologically diagnosed as benign islet cell tumors. One of them (tumor 3) exhibited a solid nodular pattern while the others showed gyriform patterns. They were divided histochemically and immunohistochemically into three types: two (tumors 1 and 2) produced a single hormone (glucagon), one (tumor 3) produced five (insulin, glucagon, somatostatin, gastrin and pancreatic polypeptide) and the remaining two (tumors 4 and 5) produced two (glucagon and pancreatic polypeptide). Electron microscopically, three types of endosecretory granules were found in the tumor cells of tumor 3 but only one type was found in tumor 4. However, in the tumor 4 extract, glucagon, pancreatic polypeptide, C-peptide, somatostatin, vasoactive intestinal peptide and growth hormone releasing factor were detected by radioimmunoassay. These findings suggest that these pancreatic tumors were both multicellular and multihormonal.     

Crystal-like deposits of amyloid in pancreatic islet cell tumors.

Numerous stellate crystal-like deposits of amyloid were observed in four human pancreatic islet cell tumors. Three of the tumors were associated with hypoglycemia or hyperinsulinemia, and the remaining one produced gastrin. Histochemical and ultrastructural studies confirmed the existence of amyloid in the deposits and also suggested the presence of adsorbed or incorporated mucopolysaccharides. Stellate amyloid deposits have previously been described in experimental systemic murine amyloidosis. The relationships of these stellate deposits to other forms of amyloid depostion are unknown.     

Pancreatic antigenic complex p64 69: involvement in regulation of insulin secretion and relation to glutamic acid decarboxylase.

The role of pancreatic beta-cell antigenic structures in modulation of insulin secretion in vitro was recently demonstrated by others. Here we report generation of a monoclonal antibody (mAB) ICA-1 to non-species specific beta-cell antigen(s) 64, 67 and 69 kDa. The mAB inhibits glucose stimulated insulin secretion in islet cell cultures. The ability of mAB ICA-1 to immunoprecipitate active glutamic acid decarboxylase from high speed supernatants of pancreatic and brain crude extracts was demonstrated. The 64, 67 and 69 kDa antigenic material was affinity purified from pancreatic islet cell high speed supernatants, active glutamic acid decarboxylase was found in the material. Immunoaffinity purification with mAB ICA-1 of GAD-like pancreatic beta-cell antigenic material has provided evidence of possible involvement of glutamic acid decarboxylase in modulation of insulin secretion.     

Immunocytochemical Localization of Glucose Transporter-2 (GLUT-2) in Pancreatic Islets and Islet Cell Tumors

Glucose is a major metabolic fuel in mammals and is transported into organs and cells by a facilitated diffusion which involves binding of glucose to glucose transporters (GLUTs). Among several GLUTs so far indentified, GLUT-2 is specifically localized immunocytochemically in beta-islet cells. Using immunocytochemical staining, normal pancreases and 27 cases of islet cell tumors, including insulinomas, gastrinomas, glucagonomas, pancreatic polypeptide-omas (PPomas), and a nonfunctioning islet cells tumor, were systematically stained for four different pancreatic hormones, gastrin, and GLUT-2. GLUT-2 staining in beta-islet cells was more diffuse than that of insulin immunostaining, and corresponded with the positive staining in the lateral segments of beta-cell plasma membrane, that faced adjacent beta-cells. Glucagon, somatostatin (SRIF) and PP cells stained weakly for GLUT-2, weaker than that of beta-cells. Some nonbeta cells, especially extra-islet PP cells were not stained for GLUT-2. Among islet cell tumors, insulinomas stained less strongly for GLUT-2 than normal beta-cells from the adjacent normal pancreas. Gastrinomas, glucagonomas, and PPomas stained weaker than insulinomas. Even nonfunctioning islet cell tumors were weakly stained for GLUT-2. The positive staining for GLUT-2 observed for islets cells and all islet tumors is consistent with the notion that all pancreatic islet cells and islet cell tumors utilize glucose as a major fuel, requiring transporter-facilitated diffusion of glucose into the cells of normal organ and their tumors.     

Histidine decarboxylase expression in pancreatic endocrine cells and related tumors

Histidine decarboxylase (HDC) is an enzyme for decarboxylating l-histidine to histamine and is expressed in various types of cells including neuroendocrine tumors. Recent findings have demonstrated a high percentage of HDC immunoreactivity in many neuroendocrine tumors, including carcinoid tumors, small cell carcinomas of the lung, pheochromocytomas, and medullary carcinomas of the thyroid. HDC immunostaining was applied to pancreatic islet cells and related tumors to explore possible expression of HDC as a wide spectrum marker for neuroendocrine differentiation. A total of 24 cases (22 pancreatic endocrine neoplasms, one small cell carcinoma of the pancreas, and one mixed exocrine-endocrine carcinoma) along with normal pancreatic tissue were immunostained with the anti-HDC antibody. In a normal pancreas, a double immunostaining revealed possible colocalization of HDC with glucagon- or insulin-positive cells in the islets. Seventeen of 22 pancreatic endocrine neoplasms (77%) were found to be positive for HDC, and no distinct relation to hormonal activity was observed. One small cell carcinoma was strongly positive to HDC. One non-functional tumor with mixed exocrine and endocrine components showed a diffuse positive immunostaining for HDC, and some neoplastic glucagon- or somatostatin (SRIF)-positive cells coexpressed HDC. In conclusion, we demonstrated that the majority of pancreatic endocrine tumors expressed HDC, and we suggest that HDC is a wider new marker for neuroendocrine differentiation.     

Cystic forms of typically solid pancreatic tumors

In addition to the well-known cystic lesions, the differential diagnosis of pancreatic cysts also includes cystic counterparts (or cystic change in) otherwise typically solid tumors of this organ. Pancreatic endocrine neoplasms (islet cell tumors) and ductal adenocarcinomas sometimes undergo cystic degeneration, the latter usually due to necrosis. Also, although acinar cell carcinoma is typically a solid tumor, its rare cystic counterpart, "acinar cell cystadenocarcinoma," has been reported. A rare variant of pancreatic ductal adenocarcinoma referred to as "large-duct-type" is characterized by microcystic ectasia of the invasive glands and may mimic other cystic tumors at the microscopic level. Secondary tumors, although exceedingly rare, may also potentially fall into the differential diagnosis of pancreatic cysts. Often, the morphological characteristics of these lesions are identical to those of their solid counterparts, and their diagnosis is not difficult if one is aware of their existence. This review focuses on these cystic counterparts of otherwise characteristically solid pancreatic neoplasms. Solid pseudopapillary tumor, in which cystic degeneration is so common that "cystic" has been a part of many alternate terms assigned to this neoplasm, is discussed in another article of this issue of Seminars in Diagnostic Pathology.     

Rapid and efficient in vitro generation of pancreatic islet progenitor cells from nonendocrine epithelial cells in the adult human pancreas

The absence of efficient and directed methods for the differentiation of adult pancreatic progenitor cell populations to pancreatic islet cells has raised doubts concerning the regeneration potential inherent in the adult pancreas. Relatively low levels of islet cell differentiation have been reported using adult pancreatic cells in vivo and in vitro. In the present study, we initially enriched for a nonendocrine epithelial component of the adult human pancreas and defined conditions that are permissive to islet cell differentiation in vitro. Sequential progression of cell differentiation in the permissive conditions allowed for incremental evaluation of changes occurring in the cell population. Optimization of the differentiation process, for the efficient production of islet endocrine cells, was accomplished by identifying specific factors and culture conditions that increased islet progenitor production 250-fold. Ultimately, 85% percent of the nonendocrine epithelial cells isolated from human pancreatic tissue and cultured in the optimized conditions for 8 days, readily re-expressed pancreatic duodenal homeobox-1 (Pdx1). Sixty-five percent of these Pdx1-expressing cells were capable of additional islet endocrine cell differentiation. This represents a significant advancement in the differentiation of an adult pancreatic progenitor cell population in vitro and suggests that the nonendocrine compartment of the human pancreas remains an important cell resource for the generation of transplantable islets to treat diabetes.     

Early changes in islet hormone secretion in the hamster pancreatic cancer model

The diabetic state that is seen at a high frequency in association with pancreatic cancer is characterized by elevated plasma levels of several islet hormones and by marked insulin resistance. Both the diabetic state and insulin sensitivity improve after tumor removal by sub-total pancreatectomy. Impaired glucose tolerance has also been found in the hamster pancreatic cancer model, but conflicting data regarding islet function have been reported. In order to further investigate islet function and secretion during early development of pancreatic cancer, we measured the concentrations of insulin, glucagon, somatostatin, and islet amyloid polypeptide (IAPP) in plasma, pancreatic tissue, and secretin-stimulated pancreatic juice at 12 and 27 weeks after the ductal-cell-specific carcinogen, BOP had been used to induce tumors in Syrian golden hamsters. At 12 weeks after BOP, plasma glucagon levels were significantly increased. An exaggerated plasma-glucose response and concomitant hyperinsulinemia were observed at 27 but not 12 weeks after BOP. Plasma IAPP concentrations, but not glucagon or somatostatin, were elevated at 27 weeks. Tissue concentrations of IAPP were substantially reduced in BOP-treated hamsters at 27 weeks. No differences in hormone concentrations were seen in pancreatic juice from the two groups at either of the two time points investigated. The study showed that islet hormone changes accompany the early development of pancreatic tumors in the hamster pancreatic model. The hormone changes and apparent insulin resistance resemble the metabolic changes found in humans with pancreatic cancer.     

In vitro induction of giant cell tumors from cultured hamster islets treated with N-Nitrosobis(2-Oxopropyl)amine

Giant cell carcinoma of the pancreas is a rare tumor. Its histogenesis is still controversial. In a Syrian hamster pancreatic cancer model, tumors similar to human giant cell carcinomas have been induced at an extremely low rate of incidence and after the use of high doses of pancreatic carcinogens. Thus far no tumors of giant cell type have been induced by the in vitro treatment of hamster pancreatic ductal cells with the potent pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine (BOP). In the present study we report the induction of giant cell carcinoma from hamster islets treated with BOP in vitro. The results suggest that in hamsters some component of islet cells, probably stem cells, are the origin of giant cell carcinoma.