Coexistence of unilateral adrenal macronodule and Cushing's disease. Report of two cases.

The coexistence of an unilateral adrenal macronodule and Cushing's disease is well documented in only few reports. We hereby describe two patients with ACTH-dependent Cushing's syndrome and asymmetric adrenal involvement. In both patients the left-sided adrenal contained a nodule sized 1.5 and 1.4 cm, respectively, while the contralateral gland appeared as normal at abdominal computerized tomography. Adrenal scintiscan revealed a bilateral uptake of the tracer. Dynamic testing of hypothalamic-pituitary-adrenal axis was suggestive of pituitary dependency but neuroradiologic imaging was inconclusive. Inferior petrosal sinus sampling demonstrated a clear center to periphery ACTH gradient and an ACTH-producing pituitary microadenoma was found and removed in both cases. Hypopituitarism ensued postoperatively and Cushing's syndrome resolved but the adrenal nodules regressed only many month after operation. The present cases confirm that the presence of an adrenal mass in a patient with Cushing's syndrome is insufficient to confidently conclude for the adrenal dependency of the syndrome.