Endocrine Abstracts

Cyclic Cushing’s syndrome (CysCS) is one of the peculiar types of Cushing’s syndrome, characterized by the iteration between remission and recurrence. The precise mechanism in which the hormonal activity is changed suddenly has not been determined, while several hypotheses have been presented. Here, we report a case of CysCS which was induced remission dramatically by dopamine agonist.

A 67-years-old woman was pointed out increasing ACTH and cortisol (F) levels during the examination for hyperglycemia and hypokalemia. Her ACTH and F were not decreased in midnight, and not suppressed by high dose dexamethasone. Then she was diagnosed as ACTH dependent Cushing’s syndrome. Although cavernous sinus sampling suggested ectopic producing of ACTH, general whole-trunk CT, MRI, and FDG–PET could not detect any ACTH producing tumor. Interestingly excess ACTH and F were normalized dramatically and completely by the short-term treatment with cabergoline (Cab), potent dopamine receptor type 2 (D2R) agonist, where after they were kept in normal range for several months without any treatment. Similar episodes were recurred three times for recent 3 years, suggesting CycCS. Every active phase was terminated by D2R agonists, while abnormal secretion of ACTH was induced by domperidone (Dpm), D2R antagonist, even in the remission phase.

The clinical course of this case suggests D2R agonists are effective in the treatment of ACTH dependent Cushing’s syndrome. In addition, this case suggests D2R might be involved in the conversion between remission and recurrence of CycCS, although the mechanism is unclear.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.