Endocrine Abstracts

Background: Ectopic Cushing’s syndrome (ECS) frequently represents a diagnostic challenge due to its complex clinical presentation.

Case presentation: A 57-year-old male presented with typical Cushingoid appearance, high adrenocorticotropic hormone (ACTH) level (138.3 pg/ml), lack of cortisol circadian rhythm and suppression in overnight 1 mg dexamethasone suppression test (DST) (1374 nmol/l). Great daily fluctuation of serum cortisol levels from very high to normal was noticed and confirmed by two different immunoassays. Pituitary CT scan showed secondary empty sella. Results of high-dose DST and corticotropin-releasing hormone stimulation test indicated ECS (cortisol 298.3…244.1 nmol/l, ACTH 15.1…17.5 pmol/l). Chest MSCT visualized a nodular lesion (11.1×7.6 mm) in the lower lobe of the left lung. The octreotide scan showed no radiopharmaceutical accumulation. 18F-FDG PET/CT showed an increased glucose uptake in the left lung nodus, but also in the thickened wall of the rectum, as well as in the sigmoid, transverse colon, appendix and ileum. Colonoscopy with biopsy diagnosed ulcerative colitis. After preoperative treatment with metyrapone, resection of the apical segment was done, and pathohistological finding demonstrated atypical bronchial carcinoid with moderate proliferation index and ACTH expression. Postoperatively, normalization of cortisol and ACTH levels occurred. Two years later, similar symptoms reappeared, recurrent pleural effusions, and elevated levels of serum cortisol (1310 nmol/l) and ACTH (127.6 pg/ml). Chest MSCT differentiated a solid micronodular change corresponding to the recurrence of the underlying disease. Stereotactic radiosurgery was performed and a reduction of the nodular lesion in the lung was achieved two months later, in addition to normalization of cortisol secretion.

Conclusion: Cyclic Cushing’s syndrome due to ectopic secretion is a rare disorder that may aggravate the interpretation of diagnostic tests and patient management.