Endocrine Abstracts

Background: Although the excision of ACTH-producing tumors or adrenal tumors is the principal treatment for Cushing syndrome (CS), pharmacologic treatment has a well-established role. Among various medical agents, ketoconazole (KTZ) has inhibitory effect over 17,20 desmolase, 17α-hydroxylase, 11β-hydroxylase, and 16α- and 18-hydroxylase; moreover, it also inhibits ACTH production and cellular growth, partly because of apoptosis induction.

Case report: A 76-year-old female was admitted with suspected hypercortisolism for further diagnostic tests. Increased serum cortisol levels with loss of circadian rhythm (1290, 1083, 1264, and 942 nmol/l at 0800, 1600, 2000, and 2400 h respectively) increased basal urinary free cortisol (basal 2804–2606 nmol/d), non-suppressible in 2 mg (1050 nmol/d) respectively 8 mg dxm test (2555 nmol/d), with increased ACTH levels (282–251 pg/ml) confirmed ACTH-dependent Cushing syndrome (CS). MRI of the pituitary was normal, CT of thorax and abdomen showed only hyperplastic adrenal glands. Bronchofibroscopy was negative, PET/CT with 18FDG showed pathologic lesion in inferior mediastinum. Patient refused to undergo thoracic surgery, thus KTZ at a dose of 400 mg/d was started. Patient tolerated medical treatment without any side effects, UFC levels decreased to normal levels (86 nmol/d) and good effect of KTZ persisted even after reduction of the dose to 100 mg/d (UFC 43.58 nmol/d). At the present time, patient is on this dose of KTZ 36 months with normalized cortisol status.

Discussion: At a dose of 400–1200 mg/day, KTZ can decrease cortisol production in patients with CS from various etiologies. Reports about paraneoplasic CS indicate complete hormonal response in up to 28% of the cases, no prospective studies have been conducted based on KTZ monotherapy. The efficacy data have been drawn from retrospective studies; here, it is reported that KTZ induced biochemical remission in 50% of the patients varying from 25 to 93%. As shown in our case, KTZ may have extraordinary effect in some patients with paraneoplastic CS.