Pediatric tumors of the urinary bladder are rare, rhabdomyosarcoma being the most frequently occurring lesion. Most are low grade and present at an early stage; reported cure rates approach 70% to 80%. Other bladder tumors are exceedingly uncommon in the pediatric age group. These include transitional cell papillomas, papillary carcinoma, inflammatory myofibroblastic tumors, and very rarely neurofibromas. Neurofibromas of the urinary tract occur infrequently: fewer than 70 cases with bladder involvement have been
reported to date and of these only 25 cases occurred in the pediatric population, with only one case described with presentation in infancy. we decided to present a case of a plexiform neurofibromatosis of the bladder in a two months old infant.

An infant at the age of 2 was referred for bilateral hydronephrosis and palpable right lower quadrant and suprapubic mass. The initial US examination showed bilateral grade IV hydronephrosis, with a mass in the region of bladder whose origin could not be determined. An initial ct scan of the pelvis was performed and an infravesical and retrovesical formation mass was clearly seen, again of open etiology (from bowel and/or mesenterial origin, to most likely mesenchimal tumor of the bladder or prostate). Initially, rhabdomyosarcoma was suspected and percutaneous biopsy was scheduled. At the same time percutaneous nephrostomy was planned due to the initial signs of the kidney insufficiency were present.

MRI showed and expansive infiltrative soft tissue tumor that surrounds like a muff caudal aspect of the bladder with both vesicoueretric orifices, prostate and part of the urethra. There is a diffuse thickening of the bladder wall that is up to 18mm thick. Total dimensions of the tumor are 64x53x56mm. Both ureters are dilated, with bilateral hydronephrosis gr IV. Inguinal lymphnodes slightly enlarged up to 6.8mm on the right and 5mm on the left. No enlarged mesenterial or retroperitoneal lymph nodes. 
Bilateral percutaneous nephrostomy was performed. Needle biopsy of the tumor with a 18 gauge needle was done. Samples were sent for pathohistology. The results showed that the tumor consisted of diffuse, moderately dense, soft collagen fibers mixed with nerve fibers, mostly with clear contures, and formed by ceels of multiplied endoneurium, diffusely infiltrated into the stroma of the tumor. In the stroma cells form moderately numerous, small round structures that correspond to Melsner bodies. There are no signs of cell atypia. Immunohisochemistry showed>S-100+, GFAP+, Chromogranin +, calretinin -, KI67 15%.

Neurofibromas, either diffuse or intraneural, are immunoreactive for both S-100 protein and type IV collagen. Most examples are
benign, although approximately 5% of plexiform examples are known to undergo malignant transformation. Only 2 published reports describe neurofibromas of the urinary bladder having undergone malignant transformation. The optimal management of patients with neurofibroma of the bladder is unclear. Significant morbidity may be associated with bladder involvement, because of urinary
tract obstruction. Furthermore, malignant transformation can occur and it is critical to distinguish benign neurofibroma from malignant lesions. Malignant transformation may be limited to small areas and could be difficult to assess, especially in plexiform tumors, in which the process is multifocal. Surgical intervention appears the treatment of choice for symptomatic patients. Conservative treatment by transuretheral or partial cystectomy may be appropriate for patients without upper tract obstruction. For patients with upper tract obstruction, urinary diversion could be required. It is important to know that the mass, if left in place, often will continue to grow and may cause local pressure effects even if benign.

Neurofibromatosis of the bladder is a rare finding, and surgery could provide a final solution for the patient. Surgery would result in cystectomy and  prostatectomy. There is also a risk of recurrent appearance of the neurofibroma at the site of the initial excision. Therefore we have a dilemma, when to performe cystectomy and prostatectomy. Percutaneous nephrostomies are still functional, but a final urine derivation is yet to be done.