Endocrine Abstracts

Introduction: ACTH-secreting macroadenomas account for about 4–10% of Cushing’s disease and are often resistant to surgical treatment and radiotherapy. The aim of the study was to present diagnostic and therapeutic difficulties in a case of cyclic recurrent ACTH-dependent Cushing’s syndrome due to atypical pituitary adenoma.

Case report: 50-year-old man with visceral obesity was referred to hospital because of poor control of diabetes and high blood pressure. On the basis of clinical symptoms and severe hypokaliemia hypercortisolemia was suspected and laboratory test were performed. They confirmed ACTH-dependent Cushing’s syndrome (plasma cortisol=46.6 μg/dl (range 4.3–22.4); ACTH=176 pg/ml (4.7–48.6); urine daily cortisol excretion=15 870 μg (range 285–213.7)]. Further investigations did not show any pathology of the pituitary or another tumor responsible for ectopic ACTH syndrome. Between 08.2007 and 03.2008 the patient received inhibitors of steroidogenesis. The loose of weight (30 kg), normalization of cortisol level and significant improvement of patient’s well-being were observed. The treatment has been withdrawn. During further follow-up of the patient there were periodically repeated periods of moderate subclinical hypercortisolemia, observed mainly in spring and autumn. In spring 2013, significant clinical and laboratory signs of hypercortisolemia appeared and MRI revealed pituitary macroadenoma (15×13×15 mm). In 09.2013 the patient underwent transsphenoidal surgery (atypical sparsely granulated coricotroph adenoma, ACTH (+), MIB1>20%). Postoperative MRI did not show tumor remnant, but moderate hypercortisolemia was present. The patient was disqualified from a second surgery, in 04.2015 he received stereotactic radiotherapy. Since November 2015 the patient is being treated with pasireotide because of persistent hypercortisolemia.

Conclusions: The authors present long-term difficulties in establishing the diagnosis of Cushing’s disease, mainly because of cyclic nature, long period of remission and diagnostic limitations in finding the source of ACTH excess. Delay in diagnosis of Cushing’s disease leads to worse effects of treatment and the need to search for new therapeutic approaches.