Nephrogenic adenoma of the ureter in a teenager with history of leukemia

Nephrogenic adenomas represent a suspected metaplastic response of the uroepithelium to chronic inflammation and are typically associated with recurrent urinary tract infections, stones, prior radiation therapy and other irritative factors, more commonly seen in adults. Nephrogenic adenoma (also known as nephrogenic metaplasia) usually involves the bladder in adults and represents a rare lesion that can easily be misdiagnosed as a malignancy. We present the case of a 14-year-old male with prior history of acute lymphoblastic leukemia (ALL) who presented with a several month history of vague flank pain which increased in intensity, leading to an emergency department presentation with the only significant finding on exam being microhematuria. Subsequent imaging showed a tumor like replacement of the right ureter with proximal hydronephrosis, initially felt to represent recurrent leukemia. Pathology revealed the tumor like ureteral replacement to represent a nephrogenic adenoma, a benign entity which often responds to conservative management, though not previously reported in the ureter in pediatrics.