K Kovacs

..Possible derivation of SAS-3 from rostral thyrotrophs, a cell type presently known in rodents is contemplated...

..The question can be raised whether chemotherapeutic agents may damage parathyroid cells leading to loss of self-tolerance and autoimmune chronic parathyroiditis...

..It appears that in our patient the clinically apparent anterior hypopituitarism was not due to the lack of storage but rather to insufficient release of adenohypophysial hormones caused by the defect in hypothalamic regulation...

..Based on the clinical, laboratory, and morphological findings, we recommend temozolomide therapy in patients with pituitary tumors not responding adequately to other treatment options...

..It can be concluded that amylin is not a satisfactory immunohistochemical marker to identify pancreatic islet tumors, medullary thyroid carcinomas and pituitary adenomas...

..Further studies are required to determine whether prolactin released from the pituitary tumor in excess played a role in the formation of microthrombi causing multiple organ failure and the demise of the patient...

..The literature regarding multiple adenomas is reviewed as are the diagnostic and therapeutic difficulties associated with these rare lesions...

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..Our aim was to obtain some insight into the possible cytogenesis of this unusual tumor...

..These results indicate that (1) both types of somatotroph adenoma cells react similarly to GHRH stimulation, despite their morphologic differences, and (2) GHRH stimulates GH synthesis as well as GH release by somatotroph adenoma cells...

..Focal PRL cell hyperplasia noted in three pituitaries could also be due to a GRF effect. Longer exposure to GRF is needed to clarify whether GRF can cause adenoma...

..More generally, these data merge essential elements of the hypothalamic and pituitary hypotheses of pituitary tumorigenesis, providing for a more unified concept of neoplastic progression in the pituitary...

..The enhanced susceptibility to develop plurimorphous adenomas of the acidophil cell line may have a genetic basis in the stable population the patients came from...

..Our data strengthen the view that these three plurihormonal adenomas of the acidophil cell line are not only morphologically but also functionally different and warrant separation...

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..Keywords: immunohistochemistry, endoglin, CD34, microvascular density, angiogenesis, pituitary...

..We investigated the immunohistochemical expression of estrogen receptors alpha (ERalpha) and beta (ERbeta) in pituitary adenoma subtypes combined with clinicopathological factors...

..The infertility of PEPCK/bGH transgenic females may be attributed to lactotroph hyperplasia and marked reduction in number of gonadotrophs...

..In addition to prolactin cells and growth hormone cells, immunoelectron microscopy showed several bihormonal mammosomatotrophs, also appropriate for pregnancy...

..Occasional examples occur in lactotroph or gonadotroph adenomas. Although electron microscopic specimens are admittedly small, the large number of investigated cases gives credence to the observations...

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..The results suggest that IGF-II, when highly expressed, may have a role in pituitary adenoma proliferation...

..In conclusion, D2R gene is expressed in the majority of pituitary adenomas representing all tumor types. The significance of nuclear localization of D2R protein remains to be clarified...

..Our study supports the view that protracted stimulation of corticotrophs resulting from the elimination of the negative inhibitory feedback effect by corticosteroids plays a role in adenoma initiation...

..To our knowledge, only 9 cases of HPC presenting as a sellar or suprasellar mass have been reported in the literature. Often, these cases can mimic and be mistaken for a pituitary adenoma...

..It appears that NCH is the result of neuronal differentiation within sparsely granulated GH cell adenomas...

..The findings confirmed the tumor to be papillary thyroid carcinoma. To our knowledge, this is the first report citing use of thyroid transcription factor-1 to establish a thyroid source of a pituitary metastasis...

..Despite several recent attempts to assess the growth rate, aggressiveness and invasiveness of pituitary tumors, more work is required to draw conclusions on their prognosis...

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..These findings provide conclusive evidence that protracted GRH stimulation of secretory activity can result in proliferation, hyperplasia, and adenoma of adenohypophysial cells...

..CONCLUSIONS: The investigation of the present case provides additional evidence that pituitary Crooke's cell adenomas may possess aggressive behavior...

..This finding has not previously been described in the literature. The diagnostic implications of this finding are complex, and the pathogenesis of psammoma body formation in this idiopathic disorder remains unknown...

..The aim of this work was to investigate the immunohistochemical expression of nestin, a member of the intermediate filament family, in adenohypophysial vasculature during development and progression of pituitary infarction...

..It is suggested that the oncocytic cells play a role in prostaglandin metabolism within the parathyroids and may have a role in the regulation of PTH secretion...

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..The patchy expression of nestin in endothelial cells remains unexplained and its significance requires further studies...

..The incidence in published surgical specimens ranges from 0.4% to 1.3%. We present a treatment dilemma of a double adenoma that had differential O-methylguanine-DNA methyltransferase (MGMT) reactivity...

..It can be concluded that the functional activity of MAP-2 is not associated with the manufacture of any specific adenohypophysial hormone(s) and is not limited to one specific cell type...

..Extranodal lesions with or without nodal involvement also occur. We report the case of a 63 year-old woman with disseminated Rosai-Dorfman disease involving the neurohypophysis and associated with adenohypophysial PRL cell hyperplasia...

..We investigated the correlation between immunohistochemical expression of the pituitary tumor transforming gene (PTTG) and pituitary adenoma subtype...

..Abnormalities in vascular architecture and marked expression of VEGF in the tumor cells may be regarded as prognostic signs to predict the formation of metastases...

..Immunopositivity was cytoplasmic and was evenly distributed. No staining was noted in normal adenohypophyses. Our results add new information to the view that Rab3B is involved in the regulation of pituitary hormone secretion...

..In the tumor, peliosis was noted. Peliosis in a pituitary adenoma is an intriguing finding. The question arises whether it represents vasculogenic mimicry...

..It is conceivable that SNAP-25 plays an important role in PRL release and is involved in the bromocriptine-induced suppression of PRL secretion from PRL-producing adenoma cells...

..Not every endothelial cell was immunoreactive for the two caveolins, suggesting that the functional status of endothelial cells is not the same within the adenomas, not even in the same capillary...

..Phamacologic inhibition of COX-2 activity might suppress angiogenesis in pituitary tumors and may provide a novel approach for medical therapy...

..This appears to be the only case of minocyclin-associated "black thyroid" in which extensive immunohistochemical investigations have been performed...

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..The lesions represent coagulative infarctions due to ischemia. The role of the respirator is believed to be buying time to allow the changes to develop...

..Recently GH receptor blockers (pegvisomant) were introduced in the treatment of GH-producing pituitary adenomas. To the authors' knowledge the effect of these drugs on the morphology of pituitary tumors has not been revealed so far...

..Multiple surgical procedures (transsphenoidal, transcranial, or a combination of both) are the first line management, followed by radiotherapy and chemotherapy...

..More studies are needed to assess whether integrin alphavbeta3 antagonists or drugs that arrest the cell cycle of endothelial cells can inhibit angiogenesis in craniopharyngiomas...

..5) Considering the multifaceted nature of FSC, it is suggested that they represent a type of pluripotent adult stem cell...

..A practical application of the preceding finding might involve the use of Cox staining to distinguish invasive medullary carcinoma cells from hyperplastic C-cells...

..The fact that these two lesions were contiguous in the surgically removed material raises the possibility that hyperplasia can precede and transform into adenoma...

..The medical therapy of acromegaly is reviewed briefly, including long-acting somatostatin analogs and pegvisomant, a GH receptor blocker...

..77; 95% CI, 1.01-885.45; P < 0.05). CONCLUSIONS: Somatotroph tumor type represents a strong clinical predictor of response to SSA treatment and will help to identify patients who warrant more vigilant management of their disease...

..The latter showed appreciable endocrine differentiation. The assumed parent cell is the folliculo-stellate cell as pluripotent adult stem cell...

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..The finding that in our case, the pleomorphic small cell component was PHRP immunopositive and the squamous cell component showed no immunoreactivity, is intriguing and remains unexplained...

..A review of the literature and a discussion of possible causes of this unique association between the ectopic corticotroph adenoma and the pituitary hyperplasia are provided...

..Herein, we review the literature relating Ki-67 expression and various other clinicopathological parameters and conclude that uniform definitions and methods, as well as new markers, are key to improved treatment of pituitary tumors...

..The causative mechanisms involved in its development are not clear. To the authors' knowledge, there have been no recent morphologic studies of the pituitary following TBI...

..The microlobules were separated by loose fibrous tissue, and there was extensive periductal fibrosis. The spectrum of the pathognomic feature of congenital pancreatic exocrine insufficiency in JBS is discussed...

..The failure of tumor shrinkage can be attributed to the presence of a double adenoma, a previously unreported cause of failure of medical therapy in prolactinoma...

..VEGFR-2 may act as a key modulator of VEGF activity in endothelial cells and nonendothelial cells, indicating that VEGF plays an important role in the behavior of craniopharyngiomas...

..The application of different reagents yielded different patterns of positivity indicating that the validity of some common immunohistochemical reagents must be re-evaluated...

..the role of pregnancy in the aggressive behavior of this tumor is discussed along with a literature review...

..Endocrine and neuroimaging as well as detailed immunohistochemical and ultrastructural studies were undertaken. The literature is also reviewed...

..The authors report a case of brown tumor of the ethmoidal sinus, documenting its clinical, neuroimaging, and pathological features with long-term follow-up results, and review previous reports on this disorder...

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..The significance of these observations regarding paracrine activities of chief and sustentacular cells remains to be determined...

..No systemic disease was found upon staging. Primary pituitary lymphoma is extremely rare. An accurate histologic diagnosis is key to successful treatment and a favorable prognosis. The literature is reviewed...

..In summary, our findings show that VEGF/Flk-1 expression in pituitary cells may be altered by different growth factors. This may affect angiogenesis and the progression of pituitary tumors...

..In addition, we discuss in vitro and in vivo therapeutic models targeting PTTG overexpression...

..ANALYSIS: The absence of Schwann cells in the central nervous system and the absence of neighboring cranial nerves in these two cases raise issues of the pathogenesis of these rare but curious lesions...

..CONCLUSIONS: Inflammatory pseudotumor of the pituitary, although rare, should be included in the differential diagnosis of a sellar and suprasellar mass...

..Histochemical and polymerase chain reaction (PCR) studies revealed neither fungi nor tubercle bacilli. We suggest that tumoral production of an as yet uncharacterized antigen may have induced the granulomatous inflammatory reaction...

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..These findings highlight the diverse gene networks and pathways through which TGFbeta operates in its effects on pituitary tumor cells...

..The histologic, immunohistochemical, and fine structural features of these tumors were unlike those of pituitary adenoma or any other primary sellar tumor. A derivation from adenohypophyseal folliculostellate cells is suggested...

..Study of transcription factors will be helpful to clarify whether adenomas with honeycomb Golgi represent exclusively gonadotroph adenomas...

..De novo malignancy in odontogenic tumors of the sella is even more unusual, but also has an ominous prognosis...

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..In summary, TBXAS appears to be one of the up-regulated downstream enzymes of Cox metabolism in pituitary tumors. Both Cox-2 and TBXAS may play an important role in pituitary tumor development and progression...

..These results indicate that activated epidermal growth factor receptor is expressed in pituitary adenomas and carcinomas. Higher levels in pituitary carcinomas suggest a role in pituitary tumor progression...

..Our case is the first PRL-producing pituitary adenoma showing incomplete neuronal differentiation lacking mature ganglion cells...

..Because it is functionally involved in cancer progression and metastasis, Gal-3 may serve as a possible therapeutic target in the treatment of pituitary tumors...

..We predict that the immunohistochemical methods now in use for assessment of tumor behavior will be complemented and partly replaced by molecular genetic procedures in the future...

..Despite the intimate association of both elements in our lesion, no transition of adenoma to sarcoma was demonstrable by immunohistochemistry or in situ hybridization studies...

..In the second part, the classification of pituitary tumors is discussed, followed by the immunohistochemical and electron microscopic findings of pituitary adenomas and pituitary carcinomas...

..The use of ACTH and Gal-3 immunostaining should help in the diagnosis of silent ACTH adenomas...

..These novel findings represent characteristic features of short-term dopamine agonist treatment, which are not seen in long-term treatment...

..It can be concluded that gamma knife surgery caused severe alterations in pituitary adenoma microcirculation indicating that vascular injury plays a crucial role in tumor shrinkage...

..These tumors are, in most cases, very small and are found incidentally at autopsy of older patients. Our case is exceptional because the tumor developed in a young woman, extended to the suprasellar region, and caused clinical symptoms...

..These results indicate that the LGALS3, hASH1, ID2, and TLE-4 genes may have important roles in the development of pituitary carcinomas...