Rumours, Untruths Coupled With Isotretinoin

18 Widespread screening for Cushing��s syndrome in overweight individuals or patients with type 2 diabetes mellitus is therefore not recommended.18,19 Instead, a case-finding approach in patients with other features of Cushing��s syndrome or uncontrolled diabetes or hypertension despite appropriate treatment may be indicated.19 selleck compound Currently, extensive use of computed tomography (CT) and magnetic resonance imaging (MRI) scans has led to an increasing number of incidentally found adrenal masses. The prevalence of these adrenal ��incidentalomas�� increases from 0.2% to 7% with increasing age.20�C22 ��Subclinical�� or subtle Cushing��s syndrome has been reported in 5%�C10% of these patients, who represent a population in which Cushing��s syndrome is more common.22,23 Classification of Cushing��s syndrome Traditionally, endogenous Cushing��s syndrome is classified as adrenocorticotropic hormone (ACTH)-dependent or ACTH-independent. ACTH-dependent Cushing��s syndrome accounts for 80%�C85% of cases. Of these, 75%�C80% are due to ACTH production from a pituitary adenoma (Cushing��s disease [CD]), 15%�C20% are due to ACTH production from nonpituitary tumors (ectopic ACTH syndrome [EAS]) and Isotretinoin hormone (CRH)-producing tumors.1,23 Most pituitary tumors are sporadic, resulting from monoclonal expansion of a single mutated cell. Rarely, they may occur as part of a genetic syndrome, the most common being multiple endocrine neoplasia type 1 and familial isolated pituitary adenomas. Ectopic ACTH secretion most often derives from small-cell carcinoma of the lung or pulmonary carcinoid tumor. Other causes include pancreatic neuroendocrine tumors (NETs), thymic NETs, gastrinomas, medullary thyroid cancer, and pheochromocytoma.24 ACTH-independent Cushing��s syndrome accounts for 15%�C20% of endogenous Cushing��s syndrome in adults; 90% are unilateral adrenal tumors. Of these, adenomas are the cause in ~80% of the cases, while the others are adrenocortical carcinoma.25 Rare adrenal causes of Cushing��s syndrome include macronodular adrenal hyperplasia, primary pigmented nodular adrenal disease (sporadic or as part of Carney��s complex) and McCune�CAlbright syndrome. In a recent study, Louiset et al described intra-adrenal INCB28060 chemical structure production of ACTH and paracrine regulation of cortisol secretion in 30 cases of bilateral macronodular adrenal hyperplasia.26 Proopiomelanocortin messenger ribonucleic acid expression was detected in all hyperplastic tissue samples and ACTH was detected in steroidogenic cell clusters throughout adrenal tissue specimens. ACTH levels were also found to be higher in adrenal venous samples of two patients compared to the periphery.26 These findings bring into question the traditional classification of ��ACTH-independent Cushing��s syndrome��.