Endocrine pathology
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Endocrine pathology · Jan 2002
Case ReportsCrooke's hyalinization in silent corticotroph adenoma: report of two cases.
Corticotroph adenomas rarely show Crooke's hyaline change in neoplastic cells, a feature similar to that of normal corticotroph cells exposed to excess cortisol. Crooke's cell adenomas are usually associated with Cushing's disease. Nonfunctioning examples are uncommon. ⋯ Hyalinization in clinically silent Crooke's cell adenoma indicates that hyaline changes do not always relate to excess cortisol. It is known that neoplastic Crooke's cells show immunoreactivity for glucocorticoid receptors stronger than nontumorous Crooke's corticotrophs. This fact suggests that receptor overexpression or lack of receptor downregulation may result in hypersensitivity of neoplastic Crooke's cells to physiologic cortisol plasma levels.
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Endocrine pathology · Jan 2002
Downregulation of E-cadherin and its undercoat proteins in pituitary growth hormone cell adenomas with prominent fibrous bodies.
The cadherin-catenin complex regulates cellular adhesion and motility, and genetic alterations in these molecules play a critical role in multistage tumorigenesis. In this study, the expression of three major type I classic cadherins E-, N-, and P-cadherin and their undercoat proteins alpha-, beta-, and gamma-catenin, and pp120 was investigated in 127 pituitary adenomas and 10 normal adenohypophyseal glands using an immunohistochemical technique with highly specific monoclonal antibodies. In normal pituitary glands, E-cadherin, catenins, and pp120 were strongly expressed on almost all hormone-producing cell-cell boundaries, N-cadherin was weakly immunoreactive on a few cell-cell boundaries, and P-cadherin was negative. ⋯ Methylation-specific polymerase chain reaction analysis revealed that the E-cadherin gene promoter region was methylated in 6 of 16 (37.5%) GH cell adenomas with prominent fibrous bodies examined, 2 of which displayed total methylation, but not in 10 GH cell adenomas without fibrous bodies. No mutation of exon 3 of the beta-catenin gene was found in 16 GH cell adenomas with prominent fibrous bodies or in 10 other subtypes of pituitary adenomas that showed unremarkable intracellular presence of beta-catenin protein. In conclusion, the decreased expression of the E-cadherin catenin complex and methylation of the E-cadherin gene promoter region only in GH cell adenomas with prominent fibrous bodies may be an event associated with the formation of fibrous bodies.