Endocrine Abstracts

Diagnosis and treatment of Cushing’s disease is one of the greatest challenges of modern endocrinology. This is related to the fact that pituitary corticotropinomas are small tumours that are difficult to visualize in magnetic resonance imaging (MR). In about 40% of patients with Cushing’s disease, MR scans of the pituitary gland do not reveal any changes. The method that allows to localize the source of adrenocorticotropin (ACTH) secretion is bilateral inferior petrosal sinus sampling (BIPSS), which has so far been performed rarely in our country. The treatment of choice of this disease is transphenoidal resection of corticotropinoma allowing remission of hypercortisolemia in 64–98% of operated patients. The results of surgical treatment depend to a large extent on locating the source responsible for excessive ACTH secretion. The aim of this study was the assessment of usefulness of bilateral inferior petrosal sinus sampling in diagnosis and treatment of Cushing’s disease in 74 patients with negative or inconclusive MR imaging of pituitary adenoma. All patients had BIPSS performed and ACTH values were used to assess the ratio of the concentration in central vs peripheral blood and between right and left inferior petrosal sinus before and after administration of CRH. Confirmation of the pituitary secretion of ACTH-dependent hypercortisolemia was obtained in 68 patients, in 6 patients the result indicated ectopic ACTH secretion. All patients with pituitary ACTH secretion underwent a transsphenoidal operation, which in three cases (4.4%) did not lead to a cure. A statistically significant correlation was also shown between BIPSS result and localization of adenoma confirmed intraoperatively. The results of bilateral inferior petrosal sinus sampling in patients with Cushing’s disease and negative or inconclusive result of pituitary imaging presented in the study allow for differentiation of the pituitary and non- pituitary source of ACTH secretion and are highly helpful in localization of corticotropinomas, as well as affect the effectiveness of surgical treatment. It has been demonstrated that the greatest diagnostic significance during bilateral inferior petrosal sinus sampling have results obtained in the 3rd minute after CRH administration and that BIPSS is a safe and well--tolerated procedure. In the group of ACTH-secreting pituitary adenomas examined, the diameter of the tumor was the only significant factor influencing the effectiveness of surgical treatment.