A case series of nephrogenic adenoma of the urethra and bladder in children: review of this rare diagnosis, its natural history and management, with reference to the literature.

Nephrogenic adenoma (NA) is a rare benign tumour of the urinary tract and is found most commonly in the bladder. Here are presented four cases of paediatric NA, two bladder and two urethral. Their diagnostic and management features in the context of differential diagnosis and natural history are discussed. A 3-year-old girl presented with recurrent urinary tract infections (UTIs) and haematuria. She had undergone a previous hemi-nephro-ureterectomy. An ultrasound scan suggested a large bladder tumour, which was biopsied cystoscopically, and histology confirmed an NA. She then underwent open resection of the tumour. A 4-year-old girl presented with recurrent UTIs and a history of previous bilateral duplex ureterostomies and subsequent trans-uretero-ureterostomy with ureteric re-implantation. A cystoscopy showed a papillary tumour, which was confirmed as NA on histology. An 11-year-old boy presented with haematuria and dysuria and no other relevant history. At urethroscopy a ragged area biopsied in the bulbar urethra showed NA. A 7-year-old boy presented with haematuria and no other relevant history. At urethroscopy an inflamed nodular area was biopsied and nephrogenic adenoma confirmed. In the two bladder cases, but not the urethral cases, a causative factor could be identified. Recurrence was noted in both of the bladder cases. The urethral cases had persistent symptoms suggestive of continuing NA. Treatment consisted of endoscopic and open ablation of the tumours, and endoscopic fulguration of recurrences for the bladder cases, and surveillance for the urethral cases. Only two previous cases of urethral and 25 cases of bladder NA have been reported in children.