Imaging can make a clear contribution while investigating underlying causes of polycythaemia, such as benign kidney pathology (renal artery stenosis; renal cysts; postrenal transplantation), adrenal disorders (Cushing’s syndrome), as well as Epo-producing tumours (renal tumour; hepatocellular carcinoma; uterine leiomyomas; cerebellar hemangioblastomas, meningioma; pheochromocytoma, paraglioma). The gene discussed is EPO; the disease is Renal cyst.