Endocrine Abstracts

Introduction: Nelson´s Syndrome is defined as the presence of an enlarging pituitary tumor associated with elevated fasting plasma ACTH levels and hyperpigmentation in patients submitted to bilateral adrenalectomy for the treatment of Cushing´s disease.

Case Report: We present a case of a 48 y/o woman who in 2015, was diagnosed of Cushing’s disease and underwent transsphenoidal adenomectomy but remission was not achieved, so the patient was then treated with ketoconazole. However, after a 2-month period bilateral adrenalectomy was performed due to persistent hypercortisolism, and the development of severe hepatitis and simultaneously she was referred to radiotherapy. Subsequently, few months after adrenalectomy, the patient developed Nelson’s syndrome with intense skin hyperpigmentation, headaches, and elevated ACTH levels (>1000 pg/ml). The magnetic resonance imaging demonstrated slight increase in size of adenoma. The patient was initially treated with cabergoline (1 mg/week) observing only a short and transient decline of ACTH so the dose was adjusted. After increasing dose of cabergoline (2 mg/week) ACTH levels decreased and the headaches and hyperpigmentation improved significantly. Four years later, plasma ACTH levels were normalized (33 pg/ml) and MRI showed the disappearance of the pituitary adenoma. In order to investigate on the direct effect played by cabergoline treatment on the remission of Nelson’s syndrome, the treatment was withdrawn. ACTH levels are normalized (50 pg/ml) since nowadays.

Discussion: This case demonstrated that cabergoline treatment is able to induce the remission of Nelson’s syndrome and may be a valid therapeutic alternative in this syndrome.

The peculiar expression pattern of D2 receptors in some non functional and corticotroph tumors could explain the favorable clinical response to cabergoline in the setting.