Endocrine Abstracts

Most pituitary operations for Cushings’s disease are technically difficult procedures. Since the souce of excessive ACTH-secretion in Cushing’s disesase is almost invariably a pituitary microadenoma, selective resection of this minute tumor is considered the primary standard therapy. However, almost half of the tumors escape direct preoperative detection even by sophisticated magnetic resonance imaging. Thus, in these the indication for surgery is based on laboratory findings of hormone determinations, including dynamic tests and selective blood sampling from the inferior petrosal sinus. Systematic sectioning of the gland is required to find the tiny tumor. Technical supports, like intraoperative sonography, have been introduced. Following successful surgery, ACTH and cortisol levels, respectively, decrease rapidly to ideally reach subnormal levels. Such an isolated adrenocortical insufficiency is a favourable prognostic indicator for long-lasting remission and requires corticosteroid substitution. Some 65–90% of patients harbouring pituitary microadenomas experience a remission after transsphenoidal pituitary surgery in experienced centers. In most series, negative imaging is an unfavourable prognostic factor. Moreover, there is a recurrence rate of some 10–20% at 10 years. Also the technical performance of such transsphenoidal sella explorations is challenging. The sella is frequently normal sized, incompletely pneumatized and thus, more venous bleeding occurs intraoperatively than with larger adenomas. Many of the patients harbour significant comorbitities. However, in some 90% of patients microadenomas are detected intra-operatively. Not in all of these, representative tissue arrives in the pathologist’s laboratory. For ill-defined tumors, lateral hemihypophysectomy, central core partial hypophysectomy or total hypophysectomy may be considered. However, the success rate of any kind of hypophysectomy in terms of normal ACTH- and cortisol secretion is lower than that of selective operations in patients with distinct radiological findings.