Remission of erythrocytosis and hypertension after treatment of a giant renal cyst.

Giant renal cysts measuring more than 15 cm in greatest diameter are uncommon and the association with erythrocytosis and hypertension is very rare. We present a case of a 22-year-old man with an incidental giant left renal cyst associated with hypertension and polycythemia that was treated by drainage and laparoscopic excision, followed by resolution of both hypertension and erythrocytosis.