Presentation of idiopathic retroperitoneal fibrosis in the pediatric population.

Idiopathic fibrosis of the retroperitoneum is rare in childhood. The authors describe an 11-year-old boy who presented with progressive renal failure, bilateral hydronephrosis, hypertension, and elevated erythrocyte sedimentation rate (ESR) owing to retroperitoneal fibrosis. Ureterolysis was performed with improvement in his creatinine level and blood pressure. The soft tissue mass consisted of dense collagenous fibers consistent with retroperitoneal fibrosis. Postoperatively, he received steroids and azathioprine. Retroperitoneal fibrosis in the pediatric population is rare with only 23 cases reported in the English-language literature. Treatment includes pulsed steroid regimens, ureteral catheterization, and retroperitoneal exploration with ureterolysis. If allowed to progress, renal failure can result and lead to death. The etiology of retroperitoneal fibrosis in the pediatric patient may include autoimmune diseases, infection, and neoplasm, but most cases are idiopathic. Retroperitoneal fibrosis should be considered in patients with an elevated ESR, hypertension, renal failure, and hydronephrosis. Evaluation also should include a search for autoimmune diseases and malignancy.