Sinus cavernosus versus sinus petrosus catheterization in Cushing's diagnosis

Abstract

The management of adrenocorticotropic hormone (ACTH)-dependent Cushing's disease implies difficulties in the differential diagnosis, and in the detection of minute pituitary adenomas of less than 4mm. The triad of detectable ACTH, suppression of cortisol in the high dose dexamethasone test, and stimulation in the corticotropin-releasing-hormone (CRH)-test has a high accuracy to prove pituitary dependency. In unclear cases, the use of inferior petrosal sinus sampling (IPSS) or cavernous sinus sampling (CSS) for the exclusion of ectopic ACTH-syndrome is currently advised especially when cranial MRI is negative. Pre-treatment with ketoconazole to improve the general condition of the patient may induce a false positive central-peripheral gradient. The reliability and safety of these methods to localise the mostly lateralized microadenomas is still discussed. Transsphenoidal micro-surgical adenomectomy, the accepted primary therapy of Cushing's disease, has been improved with endocrine-surgical tools like intraoperative ACTH-measurement from the cavernous sinus. More recently with the introduction of CSS the direct cavernous sinus sampling can be avoided. From experienced pituitary centres remission rates ranging from 80 to 98% have been published in the last decade. False diagnosis (pseudo-Cushing, ectopic ACTH-syndrome), incorrect adenoma localisation especially by IPSS, negatively influenced the surgical results. In cases with prior falsely guided hemi-hypophysectomy even a meticulous secondary operation and removal of a minute adenoma of the contralateral side may induce hypopituitarism. We compared the published results of both catheter techniques and our own recent experiences with CSS and follow-up results. The advantage of the CSS was seen in the higher rate of correct localisation (about 90%) of the mostly lateralized minute adenomas, the avoidance of simultaneous bilateral catheterization and application of CRH. So far no severe side effects as in IPSS have been seen in our small series as well as in larger published series.