MRI detection of atrophic kidney in a hypertensive child with a single kidney

The role of magnetic resonance imaging (MRI) in the work-up of secondary causes of pediatric hypertension is typically restricted to that of renovascular causes where main renal artery stenosis is suspected. We report a case of a 10-year-old female child with hypertension, who was thought to have unilateral renal agenesis, because only a solitary left kidney could be visualized on both ultrasound and renal scintigraphy. Our patient underwent magnetic resonance imaging because of suspected renal artery stenosis in her solitary left kidney. At MRI she was found to have a normal left kidney. However, a very tiny, atrophic right kidney was also visualized. A laparoscopic right nephrectomy was performed, which resulted in complete resolution of her hypertension. This case illustrates a possible additional role for MRI in a very small subset of pediatric hypertensive patients: those with a single kidney on ultrasound.