Endocrine Abstracts

Introduction: Cyclic Cushing’s syndrome (CCS) is extremely rare. It’s defined by periodic hypercortisolism with at least three proven peaks and two drops in cortisol secretion.

Case report: A 35-year-old woman was reffered for evaluation of endogenous hypercortisolism after a diagnosis of central serous coriorethinopathy. Initially she had mild symptoms. Urinary free cortisol (UFC) was 2.881 μg/24 h; ACTH 17.45 pg/ml and night salivary cortisol 7.08 mmol/l. Administration of 1 mg of dexametasone (DXM) failed to suppress cortisol secretion but adequate suppression was observed after 8 mg. Pituitary MRI was normal. Two hospital admissions over a period of 3 months showed normal UFC and night salivary cortisol and adequate suppression with 1 mg of DXM. Basal cortisol was about 7 μg/dl and response to i.v. ACTH (250 μg) was normal. During a third hospital admission due to clinical worsening UFC was >705 μg/24 h, night salivary cortisol 1.05 μg/dl, cortisol cyrcadian rhythm was absent and ACTH concentrations were 44 pg/ml. A desmopressin test showed an ACTH increase of 400%. Inferior petrosal sinus catheterization during hypercortisolism (UFC>540 μg/dl) showed no gradient between petrosal sinuses and periphery. Diagnosis of CCS due to ectopic ACTH secretion was made. Cervical, chest and abdomen CT, PET and octreoscan were normal. Eighteen months later, the patient had gained 20 kg and had developed frontal alopecia, hirsutism, ankle edema and osteopenia. A laparoscopic bilateral adrenalectomy was performed. Annual imaging and ectopic co-secretion markers remain negative 3 years after surgery.

Discussion: Of the 66 cases of CCS described until now, only two are due to ectopic occult ACTH secretion. For a correct diagnosis, frequent determination of UFC and night salivary cortisol are necessary and diagnostic tests should be performed during hypercortisolism.

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.