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.