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Pituitary adenomas are members of the family of neuroendocrine cells and tumors which have secretory granules containing chromogranins/secretogranins and other proteins. Pituitary adenomas express the neuroendocrine specific proconvertases PC1 (also known as PC3) and PC2, which are important for the proteolytic processing of chromogranins/secretogranins molecules. We examined the distribution of PC1...
Prolactin-secreting tumors are the most frequently occurring neoplasms in the human pituitary. Although the clinical syndrome associated with prolactinomas is well recognized the molecular and cellular mechanisms leading to cell transformation and development of these tumors remain elusive. In this paper we summarize recent evidence suggesting that both hypothalamic and intrapituitary defects can...
The paper concisely reviews the data on the humoral factors which regulate the anterior pituitary cell proliferation in endocrine and/or paracrine manner. Their relevance for pituitary tumorigenesis is also discussed. The role of estrogens, growth factors, neuropeptides, dopamine, interleukins and angiotensins is presented.
While double pituitary adenomas have been found in approximately 1% of autopsy pituitaries, those in surgically resected material have been only rarely reported. We report herein 6 cases of double pituitary adenomas, which consisted of two histologically and/or immunohistochemically different areas among approximately 450 surgical specimens. Five out of 6 patients were men and the age was ranged between...
We herein review published findings on the clinical characteristics of acromegalic patients harboring pituitary somatotrophinomas expressing adenylyl cyclase activating gsp mutations and present an update of our own data on a large series of 176 patients with and without these oncogenes. Gsp oncogenes are the result of point mutations in either codon 201 or 227 of the Gs-alpha subunit of the Gs-protein...
We studied the presence of von Hippel-Lindau protein (VHL-P) in 7 nontumorous pituitaries and 68 pituitary adenomas by immunocytochemistry using a polyclonal antibody which detects both normal and mutated forms. In nontumorous pituitary VHL-P was variable expressed in the cytoplasm of most adenohypophysial cells. In addition, weak diffuse staining was noted in the posterior lobe. Among the 53 VHL-P...
Comprehensive article summarizing more than 25 years of experience with pituitary hyperplasia in surgical material. Morphologic forms of hyperplasia<197>diffuse and nodular<197>are defined and, for comparison, the normal morphology, frequency and intraglandular distribution of cell types are briefly reviewed. All cell types can give rise to hyperplasia, although their frequency, extent...
The pathogenesis of corticotroph adenomas is unknown. In a recent study accumulation of p53 protein was detected by immunohistochemistry in a substantial proportion of pituitary corticotroph adenomas, and it has been suggested that it may be causally related to their development. However, other immunohistochemical studies have not confirmed the high incidence of p53 accumulation in this tumor type...
Pituitary thyrotroph hyperplasia, a rare cause of pituitary enlargement, is usually associated with protracted primary hypothyroidism. We present here a case of pituitary thyrotroph hyperplasia in a 51 year old woman who was thought to have a pituitary macroadenoma with suprasellar extension. The cytologic investigation of the intraoperative touch preparation identified hyperplastic thyrotrophs, provided...
Two of 420 patients with pituitary adenoma who underwent operation from 1989 to 1997 had thyroid stimulating hormone (TSH) producing adenoma. We investigated these TSH cell adenomas with immunohistochemical and ultrastructural methods and compared their ultrastructural features with brefeldin A (BFA, 0.5 mg/ml) treated pituitary adenoma cells. BFA-treated pituitary adenomas include a prolactin (PRL)...
The spatial and proportional representation of the various cell groups in the anterior pituitary is fairly constant, although it may differ between sexes. Recognizable changes occur in a number of physiological and pathological situations. The relative roles of hormones and growth factors in these processes are not fully elucidated, nor are their kinetics. In this paper, published work on basal proliferation,...
The prediction of tumour behaviour and response to treatment has led to interest in the assessment of the proliferative potential of tumours. Pituitary tumours are usually histologically benign but are capable of aggressive growth and local invasion, although distant metastasis is limited to the very rare pituitary carcinoma. These differences in tumour behaviour may determine both the prognosis and...
Familial acromegaly is an exceptional clinical entity when not associated with features of multiple endocrine neoplasia type 1 (MEN1). We report here 3 pedigrees in each of which 2 patients have been shown to develop acromegaly. In 5/6 patients, clinical follow-up, and biological screening allowed to confidently exclude MEN1. Absence of mutation in the MEN1 gene after direct DNA analysis in 2 pedigrees...
GH-producing adenomas clinically are endocrine-active tumors accompanied with acromegaly in most instances. However, GH-producing adenomas apparently unassociated with acromegaly, or so-called silent somatotroph adenomas (SSA), have recently been reported but rarely. The reported cases are characterized by normal or slightly elevated serum levels of GH but without acromegaly. Tumor cells contain moderate,...
Case history, light and electron microscopic findings of a case of a lymphocytic hypophysitis in coincidence with a suprasellar germinoma in a 12-year-old girl are reported. The girl presented with a long time case history of diabetes insipidus and subsequent panhypopituitarism. Two years after the diagnosis of diabetes insipidus magnetic resonance imaging (MRI) showed a tumorous enlargement of the...
We report the third case of a composite corticotroph pituitary adenoma with interspersed adrenocortical cells. The 16-year-old male patient presented with findings of delayed growth and pubertal arrest. In contrast to the previous two cases, this patient's tumor showed evidence of function as demonstrated by an elevated urinary cortisol level. Imaging studies revealed a sellar mass that was excised...
Recent studies indicate that cells of various epithelial tumors are capable of transformation to neurons. Observing both neurons and neuropil in two prolactin-producing adenohypophyseal tumors, one benign and one malignant, we sought to assess their cellular differentiation, the presence of nerve growth factor receptor, and expression of the dopamine receptor gene using immunocytochemistry, electron...
A 11-year-old boy presented with right temporal hemianopsia and was evaluated of a possible pituitary adenoma. At the age of six, he underwent surgery for facial deformities due to fibrous dysplasia. On admission, he had acromegalic features, was 170 cm tall, weighing 66 kg. The left side of his face was slightly deformed, and a café-au-lait spot was found on his right face. Endocrinologic examination...
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