Ureteropelvic junction obstruction due to inflammatory pseudotumor masquerading as hydronephrosis because of a neuropathic bladder in a child with myelomeningocele.

Inflammatory pseudotumors (IPTs), also known as inflammatory myofibroblastic tumors, are rare solid lesions, generally thought to be benign, which have been described in a variety of locations. We report a case of a child with a neuropathic bladder who developed a pseudotumor of the retroperitoneum that caused progressive ureteral obstruction distal to the ureteropelvic junction. Hydronephrosis as a complication of IPTs has been described with bladder and uterine IPTs; however, in our review of published reports, we found no reported cases of a retroperitoneal IPT causing proximal ureteral obstruction in a pediatric patient.