Successful treatment of ectopic Cushing's syndrome with the long-acting somatostatin analog octreotide.

We report on the efficacy of the long-acting somatostatin analog octreotide in a 43-yr old woman with ectopic ACTH syndrome. Plasma cortisol, ACTH, beta-endorphin (beta-END) and urinary free cortisol (UFC) were elevated (range 743-920 nmol/l, 29.2-49.7 pmol/l, 71.0-84.1 pmol/l, 2117-3119 nmol/day respectively). Ovine CRH (oCRH) and high dose dexamethasone did not affect cortisol and ACTH levels, while UFC significantly decreased after dexamethasone. Initially radiological investigation failed to localize the ACTH secreting tumor. Ketoconazole was not tolerated. Plasma cortisol significantly decreased both after single (100 micrograms sc) (baseline 531 nmol/l, nadir 218 nmol/l) and 3-day octreotide administration (from 810 to 448 nmol/l); plasma ACTH decreased slightly (from 30.4 to 21.3 pmol/l and from 32.4 to 22.5 pmol/l respectively); UFC decreased from 2616 to 711 nmol/day after the 3-day test. Long-term octreotide treatment (100 micrograms/8h per 54 weeks) led to clinical and biochemical improvement and recurrence followed drug withdrawal; no side effects were observed. Six months after octreotide administration a 2 cm lung mass was detected with CT and MR. Surgery was performed and a bronchial carcinoid was removed. Immunoreactive ACTH in the tumor has been demonstrated by histochemistry. Postoperatively a lasting remission of Cushing's syndrome was observed without further therapy.