Endocrine Abstracts

Introduction: The diagnosis of Cushing’s syndrome is often challenging considering that none of the used laboratory tests has an ideal diagnostic accuracy. The complexity of the diagnosis increases in cyclic disorder, which is characterized by repeated episodes of cortisol excess followed by periods of normal cortisol secretion.

Case report: A 32-year-old woman with history of arterial hypertension and obesity presented with weight gain, hirsutism, abdominal striae, uncontrolled hypertension, proximal muscle weakness and peripheral edema. Her plasma cortisol and ACTH levels were 33.8 mcg/dl (6.2–19.4) and 52.5 ng/l (<63.3), respectively. 24-hour urinary-free cortisol levels were 930 mcg/day (36–137). The 1-mg overnight dexamethasone suppression test revealed a morning serum cortisol concentration of 24.3 mcg/dl (<1.8). Pituitary MRI identified a lesion in the lateral aspect of the left lobe of adenohypophysis with ≈4 mm. She performed a 48-hours 2 mg/day low-dose dexametasone test 3 months later that showed a final cortisol level of 1.3 mcg/dl (<1.8). The patient was revaluated 4 months later and she was clinically better. Six months later she presented with relapsed symptoms. Several samples of late-night salivary revealed mixed results: 0.680/0.223/0.395/1.680 mcg/dl (<0.32). A new pituitary MRI showed a slight increase in the aforementioned area, now measuring≈5.3 mm. The patient performed another 48-hours low-dose dexametasone supression test with a final plasma cortisol level of 31.3 mcg/dl, and then a high-dose dexametasone supression test with initial and final cortisol levels of 29.5 and 16.3 mcg/dl, respectively, confirming ACTH-dependency (74.7 pg/ml). The patient underwent transsphenoidal surgery to remove the pituitary lesion. Anatomopathological analysis revealed pituitary tissue with no significant changes.

Conclusions: This case report documents a cyclical Cushing’s disease. The duration of the periods of normal and abnormal cortisol secretion can vary significantly, so the correct diagnosis can be a challenge in clinical practice.