Primary hypercortisolism and phaeochromocytoma next to, but not related to, each other

This is the first report of unilateral hypercortisolism and phaeochromocytoma that cannot be explained by medullary tumourigenic adrenocorticotropic hormone (ACTH) excretion. The patient was referred for an adrenal incidentaloma with hypertension but no Cushingoid features, disturbed glucose tolerance and osteopaenia. Additional testing revealed hypercortisolism with suppressed ACTH, and a right-sided phaeochromocytoma with typical radiographic appearance. Resection of the right adrenal completely normalised the clinical symptoms and biochemistry, and increased ACTH concentrations, implicating initial suppression. Histology revealed a tumour consisting of chromaffin cells, with only pre-existing cortical tissue containing groups of ACTH-positive cells. Recent human studies in primary Cushing's syndrome demonstrated that a paracrine effect of these aberrant cells, assumed to be Leydig cells in origin, results in hypercortisolism by stimulation of surrounding steroidogenic cells, leading to systemic ACTH suppression. We propose that 2 diagnoses within 1 adrenal, being phaeochromocytoma and autonomous cortisol overproduction due to adjoining aberrant ACTH-producing cells, explain the clinical picture.