Endocrine Abstracts

Cyclic Cushing’s disease is a rare situation due to episodic hypersecretion of ACTH. Suspicion is raised when strong clinical stigmata occur, with normal basal values of cortisol and normal responses to dynamic tests. After performing several tests, particularly during phases without symptoms (well-being), the probability of successful diagnosis increases.

We describe the case of a 33 years old female patient with full-blown clinical picture (weight excess, hirsutism, hypertension, muscular weakness, moon facies, buffalo hump and supraclavicular fat pads) since about a year. Repeated FUC showed fluctuating values – 112, 200 and 68 μg/24 h (N: 10–80). Plasma cortisol values at 8 am and 11 pm were respectively 11 μg/dl and 13 μg/dl. ACTH was 26 pg/ml at 8 am and 34 pg/ml at 11 pm. Low dose DXM suppression test suppressed plasma cortisol to 1.1 μg/dl. Pituitary MRI suggested a ‘pars intermedia cyst’. An Inferior petrosal sinus sampling study (IPSS) was performed in an asymptomatic phase: ACTH reached 703 pg/ml in the right side and 541 pg/ml in the left side. Patient was submitted to transsphenoidal surgery (pathology: corticotrophinoma). After surgery, blood pressure normalized, hirsutism and body weight decreased. Six weeks after surgery, hormonal study showed: ACTH 10 pg/ml (8 am) and 7.4 pg/ml (11 pm); cortisol 7.4 μg/dl (8 am) and <1 μg/dl (11 pm); Cortisol after overnight 1 mg dexamethasone suppression test <1.0 μg/d;. There were no other pituitary hormonal disturbances. Three months later, MRI was repeated, with no evidence of relapse or tumoral residue.

Conclusions: The strong suspicion of Cushing syndrome justified keeping on with imagiologic and hormonal studies, in spite of normal DXM suppression test and slightly elevated FUC at the beginning. The hypercortisolism alternating with normal hormonal secretion suggests that we are facing a cyclic Cushing syndrome.