1/21. Expression of vesicular monoamine transporters in endocrine hyperplasia and endocrine tumors of the oxyntic stomach.BACKGROUND: Gastric enterochromaffin-like (ECL) cells selectively express the vesicular monoamine transporter (VMAT) VMAT2, and enterochromaffin (EC) cells the VMAT1 isoform. Aims: We investigated whether VMAT isoform selection indicates the origin of endocrine hyperplasia and neoplasia from oxyntic ECL or EC cells and may be of prognostic significance in different types of gastric carcinoids. methods: Tissue from patients with chronic atrophic gastritis (CAG), Zollinger-Ellison-syndrome (ZES), gastric carcinoids and neuroendocrine carcinoma (NEC) was investigated by immunohistology and in situ hybridization. RESULTS: endocrine cells forming diffuse, linear, and micronodular hyperplasia in CAG and ZES, as well as oxyntic microcarcinoids expressed both VMAT2 and chromogranin a (CgA) but neither VMAT1 nor serotonin. In five of six sporadic carcinoids VMAT2 and CgA but not VMAT1 were detected. One carcinoid was copositive for VMAT1 and serotonin but negative for VMAT2. Electron microscopy confirmed the VMAT2-positive tumors as ECLoma and the VMAT1-immunoreactive carcinoid as EComa. CONCLUSIONS: VMAT2 and VMAT1 are reliable markers for differentiation of gastric endocrine hyperplasia and neoplasia from ECL and EC cells, respectively. The significance of VMAT2 and VMAT1 as prognostic markers lies in the relatively poor prognosis for EComa compared to ECLoma, characterized by VMAT2 positivity. The absence of both VMAT2 and VMAT1 in NEC may indicate poor prognosis.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/21. Transdifferentiation of somatotrophs to thyrotrophs in the pituitary of patients with protracted primary hypothyroidism.In patients with protracted primary hypothyroidism, the pituitary is enlarged due to the lack of feedback inhibition by thyroid hormone. In the present work, adenohypophysial biopsies from three women with protracted primary hypothyroidism were investigated by routine histology, immunocytochemistry, double immunostaining, immunoelectron microscopy, and combined immunocytochemistry - in situ hybridization. These methods confirmed the presence of massive thyrotroph hyperplasia and the formation of "thyroidectomy" or "thyroid deficiency" cells. A number of thyroidectomy cells were found to be immunoreactive for growth hormone (GH). Double immunostaining and immunoelectron microscopy revealed the presence of bihormonal cells containing both GH and thyroid stimulating hormone (TSH). Immunostaining combined with in situ hybridization revealed GH immunoreactive cells expressing TSH mRNA as well as TSH immunopositive cells expressing GH mRNA. Our findings provide conclusive evidence that somatotrophs may transform to thyrotrophs. Thus, in addition to multiplication of thyrotrophs, transdifferentiation of GH cells to thyrotrophs contributes to the increase of TSH-producing cells. The presence of such bihormonal cells best termed "thyrosomatotrophs" supports the concept that adenohypophysial cells are not irreversibly committed to the production of one single hormone and that their phenotype can change in response to functional demand.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
3/21. GIP-dependent adrenal Cushing's syndrome with incomplete suppression of ACTH.ACTH-independent Cushing's syndrome may be due to the development of ectopic hormone receptors in adrenal tissue. Thus, in food-dependent Cushing's syndrome the adrenals aberrantly express receptors for gastric inhibitory polypeptide (GIP). We present the case of a 60-year-old woman with food-dependent Cushing's syndrome whose cortisol levels increased after stimulation with CRH. In this patient with Cushing's syndrome the finding of low basal plasma cortisol levels in the late night and early morning as well as a paradoxical rise of plasma cortisol during a 7-h infusion with dexamethasone (carried out without any restriction in food intake), suggested that cortisol production was stimulated at times of food intake. Hourly measurements of plasma cortisol for 48 h revealed prominent meal-related peaks. A plasma cortisol response, elicited by oral glucose administration, could be prevented by octreotide. plasma ACTH was low or undetectable. CRH administration was followed by a ACTH response from 3 to 16 ng/l and a plasma cortisol response from 230 to 680 nmol/l. octreotide treatment for nearly five months induced a partial clinical and biochemical remission. Total bilateral adrenalectomy was performed. The left adrenal was grossly enlarged (7 x 5.5 x 4 cm) and the right adrenal was slightly enlarged (6 x 4 x 1.8 cm). Microscopy revealed bilateral nodular hyperplasia. Cell suspensions of adrenal tissue from the patient did respond in a dose-dependent fashion to stimulation with GIP and were very sensitive to stimulation with synthetic ACTH1-24. However, CRH had no significant effect on cortisol production in vitro. Using RT-PCR amplification and cDNA hybridization, GIP receptor was found to be overexpressed in the left and right adrenal tissues from this patient as compared to adrenal tissues from a normal individual or from non GIP-dependent adrenal Cushing's syndrome. There was no evidence of presence of adrenal CRH receptors. Thus, in this patient with food-dependent Cushing's syndrome, the CRH-induced plasma ACTH and cortisol response is probably mediated by an incomplete suppression of the HPA axis as a result of the intermittent food-dependent nature of Cushing's syndrome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/21. Colorectal carcinomas arising in the hyperplastic polyposis syndrome progress through the chromosomal instability pathway.The hyperplastic polyposis syndrome is characterized by the presence within the colon of multiple large hyperplastic polyps. We describe a case of hyperplastic polyposis syndrome associated with two synchronous carcinomas, one of which arises within a pre-existing hyperplastic lesion. comparative genomic hybridization was used to determine genetic changes in both carcinomas and several associated hyperplastic lesions. Microsatellite analysis at five loci was performed on carcinomas and representative hyperplastic polyps, and p53 status was analyzed by immunohistochemistry. Both carcinomas showed multiple genetic aberrations, including high level gains of 8q and 13q, and loss of 5q. These changes were not seen in the hyperplastic polyps. microsatellite instability was not seen in the carcinomas, four separate hyperplastic polyps, the hyperplastic polyp with mild adenomatous change associated with the carcinoma, or a separate serrated adenoma. allelic imbalance in the cancers at D5S346 and D17S938 suggested allelic loss of both p53 and APC, as well as at the loci D13S263, D13S174, D13S159, and D18S49. An early invasive carcinoma in one hyperplastic polyp stained for p53 protein, but the associated hyperplastic polyp was negative. In this case, neoplastic progression followed the typical genetic pathway of common colorectal carcinoma and occurred synchronously with mutation of p53.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/21. Reversible transdifferentiation: interconversion of somatotrophs and lactotrophs in pituitary hyperplasia.Previous studies conclusively demonstrated transformation of somatotrophs into bihormonal mammosomatotrophs in gestational lactotroph hyperplasia during pregnancy. Similar transdifferentiation of somatotrophs into thyrotrophs through bihormonal intermediate thryrosomatotrophs was documented during thyrotroph hyperplasia in both rodent and human pituitaries in hypothyroidism. The cessation of the stimulation resulted in reversal of the process in both conditions. The conversion of lactotrophs into somatotrophs was suggested but not documented previously in the human gland. The present study was undertaken to investigate cases of somatotroph hyperplasia by transmission electron microscopy, immunoelectron microscopy using double immunogold labeling for growth hormone and prolactin, as well as combined immunocytochemistry and in situ hybridization. Adenohypophysial tissue was removed from a 38-year-old man and a 29-year-old woman with long-standing acromegaly due to ectopic overproduction of growth hormone-releasing hormone (GRH) by bronchial carcinoid tumors. For comparison, two pituitary biopsies were studied: one from a 38-year old woman with idiopathic lactotroph hyperplasia and one from a 14-year-old boy with secondary lactotroph hyperplasia due to a suprasellar craniopharyngioma. In the patients with somatotroph hyperplasia, the prevailing cell type was the hyperplastic somatotroph joined by mammosomatotroph deriving from lactotrophs, whereas monohormonal lactotrophs were rare. The predominance of mammosomatotrophs and active lactotrophs was documented in the patient with idiopathic lactotroph hyperplasia, whereas the case of the patient with secondary lactotroph hyperplasia was characterized by monohormonal lactotrophs and somatotrophs, but mammosomatotrophs were rare. That finding in the pituitary of the boy suggests that participation of mammosomatotrophs in lactotroph hyperplasia is not unconditional Our findings conclusively demonstrate conversion of lactotrophs into mammosomatotrophs during somatotroph hyperplasia, providing further evidence for the potential of reversible transdifferentiation between somatotrophs and lactotrophs in response to functional demand.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/21. Postmortem diagnosis of "occult" klinefelter syndrome in a patient with chronic renal disease and liver cirrhosis.This report describes a patient not suspected of having klinefelter syndrome during life but diagnosed with it following postmortem examination using fluorescent in situ hybridization (FISH) for sex chromosomes and hormone serum analysis. A 49-year-old Japanese man had a history of nephrosis, heavy alcohol consumption, diabetes mellitus, and liver cirrhosis and had been undergoing dialysis for 10 years. He died of ruptured esophageal varices. autopsy revealed hypogonadism, suggesting klinefelter syndrome. This was confirmed by FISH, which showed a mosaic 46XY, 47XXY karyotype, and by serum analysis, which revealed high luteinizing hormone and follicle-stimulating hormone and low testosterone levels. autopsy also revealed a nodular, bilateral, testicular Leydig cell hyperplasia. This report illustrates the value of postmortem laboratory investigations, particularly FISH for sex chromosomes and serum hormone analysis, for the demonstration of clinically uncertain or "occult" klinefelter syndrome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/21. Severe gastritis secondary to Epstein-Barr viral infection. Unusual presentation of infectious mononucleosis and associated diffuse lymphoid hyperplasia in gastric mucosa.infectious mononucleosis is usually a self-limited clinical syndrome caused by primary Epstein-Barr virus infection. It is occasionally compounded by severe complications involving many different organ systems. Predominant gastrointestinal involvement is rarely documented. We present an unusual case of acute Epstein-Barr virus infection-associated gastritis with diffuse atypical lymphoid hyperplasia in gastric mucosa. The clinical, radiographic, histopathologic, immunohistochemical, and in situ hybridization features needed for accurate diagnosis and differentiation from gastric malignancies are discussed.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/21. Detection of Epstein-Barr virus dna from a lymphoma-like lesion of the uterine cervix.The case of a 60-year-old woman in whom a lymphoma-like lesion of the cervix was found during an episode of silent Epstein-Barr virus (EBV) infection is presented. Fractional curettage was performed because of abnormal endometrial smear. The endocervical curettage specimens were diagnosed as highly suggestive of malignant lymphoma, but microscopic examination of a subsequent hysterectomy specimen revealed a benign lymphoid hyperplasia. Those were retrospectively interpreted as a lymphoma-like lesion of the cervix. In the absence of clinical symptoms of infectious mononucleosis, the results of serologic tests for EBV revealed an active EBV infection. EBV dna was demonstrated in nuclei of large lymphoid cells in endocervical curettage specimens by in situ hybridization. She is alive and well 32 months postoperatively. When female patients with lymphoma-like lesions of the lower genital tract are encountered, examinations for EBV are recommended.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
9/21. Ectopic bioactive luteinizing hormone secretion by a pancreatic endocrine tumor, manifested as luteinized granulosa-thecal cell tumor of the ovaries.Endocrine pancreatic tumors are rare neoplasms consisting of multipotent cells capable of secreting various bioactive substances causing characteristic clinical syndromes. Ovarian stromal hyperthecosis is characterized by varying degrees of luteinized stromal cell proliferation after sustained LH and/or human chorionic gonadotropin stimulation, clinically manifested by symptoms/signs of virilization resembling the polycystic ovary syndrome (PCOS). We report a case of ectopic bioactive LH production from a pancreatic endocrine tumor in a 33-yr-old woman with rapidly developing symptoms/signs of hyperandrogenism and markedly elevated serum androgen and LH levels leading to hyperthecosis and bilateral luteinized granulosa-thecal cell tumors of the ovaries. Although the patient was initially thought to have either severe PCOS or an LH-secreting pituitary tumor, an LH-producing pancreatic endocrine tumor bearing somatostatin receptors was demonstrated on scintigraphy with [111In]octreotide and abdominal imaging. Symptoms and signs of hyperandrogenism resolved after the resection of the tumor. immunohistochemistry, in situ hybridization, and electron microscopy studies confirmed LH synthesis by the tumor cell. Although extremely rare, ectopic LH production from nonpituitary endocrine tumors should be considered in the differential diagnosis of hyperandrogenism, particularly when associated with highly elevated serum LH levels.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
10/21. Follicular lymphoid hyperplasia of the oral cavity representing progressive transformation of germinal center.Follicular lymphoid hyperplasia (FLH) of the oral cavity is a rare and poorly understood lymphoproliferative disorder. We present a case of FLH of the oral cavity presenting with progressive transformation of germinal center (PTGC). The patient was a 49-year-old Japanese woman presenting with a hard mass in the right cheek. The resected specimen contained numerous lymphoid follicles with active germinal centers and a portion of the lymphoid follicles exhibited PTGC. The PTGCs contained a few large lymphoid cells resembling lymphocytic and histiocytic reed-sternberg cells of nodular lymphocyte-predominant Hodgkin lymphoma. The PTGC was surrounded by groups of epithelioid cells. in situ hybridization studies demonstrated strong expression of Epstein-Barr virus (EBV)-encoded small rna in scattered large lymphoid cells in the PTGC. Although the etiology of FLH of the oral cavity remains unclear, the present case suggests that a subset of FLH of the oral cavity appears to be an EBV-associated lymphoproliferative disorder.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
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