Unilateral hydronephrosis in an adult woman.

A 39-year-old woman was referred for evaluation of an left hydronephrosis found on abdominal sonography. She had experienced lower back pain prior to her premenstrual period for one year. The results of a urinary analysis and the serum creatinine level were normal. Computed tomography (CT) of the abdomen and pelvis demonstrated that the left upper ureter was extrinsically compressed by a dilated ovarian vein (Pictures 1, 2). The patient’s effective renal plasma flow and glomerular filtration rate of the left kidney measured with technetium-99 m diethylene triamine pentaacetic acid were relatively normal. She was placed on regular follow-up without any surgical intervention. Ovarian vein syndrome (OVS) was first described by Clark JC in 1964 and is defined as an abnormally dilated ovarian vein with extrinsic obstruction of the ureter (1), leading to intermittent flank pain. Contrast-enhanced CT is therefore effective for establishing the diagnosis of OVS (2). The management of OVS is usually conservative. OVS should thus be kept in mind as an important cause of hydronephrosis in female patients.