title: The role of bilateral inferior petrosal sinus sampling in the diagnosis of Cushing's syndrome.
abstract: Adrenocorticotropin hormone (ACTH)-dependent Cushing's syndrome is most often due to a pituitary corticotroph adenoma, with ectopic ACTH-secreting tumors representing approximately 15% of cases. Biochemical and radiological techniques have been established to help distinguish between these two entities, and thus aid in the localization of the neoplastic lesion for surgical resection. The test that offers the highest sensitivity and specificity is bilateral inferior petrosal sinus sampling (BIPSS). BIPSS is an interventional radiology procedure in which ACTH levels obtained from venous drainage very near the pituitary gland are compared to peripheral blood levels before and after corticotropin hormone (CRH) stimulation. A gradient between these two locations indicates pituitary Cushing's, whereas the absence of a gradient suggests ectopic Cushing's. Accurate BIPSS results require hypercortisolemia to suppress normal corticotroph ACTH production and hypercortisolemia at the time of the BIPSS to assure excessive ACTH secretion. In some cases, intrapituitary gradients from side-to-side can be helpful to localize small corticotroph adenomas within the sella. BIPSS has rare complications and is considered safe when performed at centers with experience in this specialized technique.
authors.affiliation: Neuroendocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Utz
authors.forename: Beverly M K
authors.initials: BM
authors.lastname: Biller
mesh_terms: D000182:ACTH Syndrome, Ectopic / Q000175:diagnosis*; D049913:ACTH-Secreting Pituitary Adenoma / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D000236:Adenoma / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000097:blood; D003346:Corticotropin-Releasing Hormone; D003480:Cushing Syndrome / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D006801:Humans; D017591:Petrosal Sinus Sampling; D010911:Pituitary Neoplasms / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D012680:Sensitivity and Specificity
chemical_list: D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone