Isolated ACTH deficiency: an uncommon cause of hyperferritinaemia.

Isolated adrenocorticotropic hormone deficiency (IAD) is a rare disorder but not a known cause of hyperferritinaemia. We here report a man with IAD who presented with mild anaemia and unexpected hyperferritinaemia (serum ferritin, 1796 µg/L). He had high serum hepcidin and relatively low erythropoietin levels for his anaemia, with hepcidin and ferritin levels reducing with hydrocortisone supplementation. We speculate that low glucocorticoid levels might suppress erythropoiesis and anti-inflammatory activity, resulting in a higher hepcidin level and hyperferritinaemia. The possibility of adrenal insufficiency including IAD should be considered as a differential diagnosis in patients with unexplained hyperferritinaemia.