[Cushing's syndrome: special issues]

Two cases of Cushing's syndrome due to primary bilateral macronodular adrenal hyperplasia secondary to aberrant adrenal expression of hormone receptors

OBJECTIVES

Primary bilateral macronodular adrenal hyperplasia is an uncommon cause of endogenous Cushing's syndrome characterized by the presence of aberrant adrenal expression of ectopic receptors that regulate steroidogenesis by mimicking the events triggered by ACTH receptor activation. Receptors of this type have been described for several hormones. The aim of the study is to detect these receptors in two patients with ACTH-independent hypercortisolism by means of the application of a screening protocol.

DESIGN AND METHODS

A protocolized study of aberrant receptors was performed including measurements of ACTH, cortisol and other steroids and hormones. Upright posture test, mixed food and administration of Gonadotropin-Releasing Hormone (GnRH) were used as stimuli. In both patients, a stimulation test with intravenous ACTH was conducted to determinate the cortical response capacity. The study was carried out in three separate days.

RESULTS

The first patient, who had a hypergonadotropic hypogonadism, presented anomalous cortisol response to the GnRH stimulation, with potential medical treatment by the use of exogenous testosterone. In the second case, the patient with clinical Cushing's syndrome presented anomalous cortisol response to standing, whose potential medical treatment would be the use of beta-blockers.

CONCLUSIONS

This etiological variant of ACTH-independent Cushing's syndrome leads to the use of specific pharmacologic therapies in some cases as alternatives to adrenalectomy. The studied cases show the importance of having a high degree of suspicion when diagnosing less frequent types of Cushing's syndrome.

Diagnosis and treatment of adrenocorticotrophic hormone-independent macronodular adrenocortical hyperplasia: A report of 23 cases in a single center

The aim of the present study was to present the treatment observations of patients with adrenocorticotrophic hormone (ACTH)-independent macronodular adrenal hyperplasia (AIMAH) from a single medical center. A total of 23 patients with AIMAH were retrospectively reviewed according to the clinical features of the patient. Physical symptoms and biochemical evidence of Cushing’s syndrome (CS) were present in all the cases. High and low dose dexamethasone failed to suppress cortisone secretion on the suppression tests and ACTH levels were low in all the cases. Bilateral enlarged adrenal glands were observed with computed tomography scans in the 23 cases, which were determined to be bilateral adrenal macronodular hyperplasia by pathological analysis. Normal blood pressure was observed in eight patients in the 2–8 years following the bilateral adrenalectomy. A total of 15 cases underwent single side adrenalectomy and their blood pressures markedly decreased three years following surgery; medical treatment was administered to 12 of the 15 patients, while three patients underwent a contralateral adrenalectomy. Nelson’s syndrome was not diagnosed for any of the cases. AIMAH has unique endocrinological, radiological and pathological features, presenting as an independent etiological factor of CS. Diagnosis of AIMAH is usually derived from pathological examination and long term remission may be achieved by unilateral adrenalectomy. Contralateral adrenalectomy should be performed in cases of recurrence, when followed with periodical examination of the symptoms and the serum concentration of cortisol.