An unusual case of ectopic corticotrophin-releasing hormone syndrome caused by an adrenal noncatecholamine-secreting pheochromocytoma: a case report

Background: Pheochromocytoma, especially for noncatecholamine-secreting pheochromocytoma, is an extremely rare cause of ectopic corticotrophin-releasing hormone (CRH) syndrome. Case presentation: A 27-year-old Chinese woman was administered dexamethasone for a skin allergy, but her general condition rapidly deteriorated over a month. She was subsequently hospitalized for typical clinical features of Cushing's syndrome. Endocrinological investigation confirmed severe hypercortisolism along with elevated plasma adrenocorticotropin hormone (ACTH). However, magnetic resonance imaging (MRI) revealed no pituitary adenoma. Abdominal contrast-enhanced computed tomography (CT) revealed a 6.5 cm heterogeneous right adrenal mass with mildly contrast enhancement. The tumor was found during a routine physical check-up at a local hospital 16 months ago; however, the patient did not have any symptoms and did not seek further medical attention at that time. Laparoscopic resection of the right adrenal tumor led to a rapid remission of Cushing's syndrome. Based on pathological findings and the presence of normal catecholamine metabolites in her serum and urine, the patient was diagnosed with noncatecholamine-secreting pheochromocytoma. Immunohistochemical staining of the adrenal tumor revealed positive staining for CRH and negative staining for ACTH. Conclusions: This is an extremely rare case of ectopic CRH syndrome caused by an adrenal noncatecholamine-secreting pheochromocytoma. Both ectopic ACTH syndrome and ectopic CRH syndrome should be considered in patients presenting with ACTH-dependent Cushing's syndrome caused by extrapituitary diseases.