Recurrent nephrogenic adenoma in a 10-year-old boy with prune belly syndrome : a case presentation
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- Vemulakonda, V.M., Kopp, R.P., Sorensen, M.D. et al. Pediatr Surg Int (2008) 24: 605. doi:10.1007/s00383-007-2082-8
Nephrogenic adenoma is a rare benign lesion of the urinary tract that is associated with a history of irritation or injury of the urothelium. Predisposing factors include infection, calculi, surgery, trauma, and renal transplantation. Nephrogenic adenoma commonly presents with lower urinary tract symptoms or hematuria. We present the case of recurrent nephrogenic adenoma in a 10-year-old boy with a history of prune belly syndrome and discuss management of this disease in the pediatric population. To our knowledge this represents the first reported case of recurrent nephrogenic adenoma associated with prune belly syndrome.
KeywordsNephrogenic adenomaPrune belly syndromePediatric bladder tumor
Nephrogenic adenoma is an uncommon, generally benign lesion that is associated with urothelial injury . Historically, it has been considered a metaplastic response of the urothelium to injury, giving rise to papillary lesions that histologically resemble renal tubular epithelium. However, recent data suggests a renal etiology for this lesion. We report a case of recurrent nephrogenic adenoma in a child with prune belly syndrome.
A 10-year-old boy with prune belly syndrome presented with a 6-month history of dysuria with a diagnosis of “recurrent urinary tract infections” and penile pain. Urinalyses were positive for microscopic blood; urine cultures demonstrated no bacterial growth. Past surgical history was significant for neonatal abdominoplasty and bilateral ureteroneocystostomy at the age of 1. Voiding cystography showed a large capacity bladder with no evidence of vesicoureteral reflux. Renal ultrasonography showed bilateral Society for Fetal Urology (SFU) grade I hydronephrosis, with no evidence of obstruction on Lasix renography.
Nephrogenic adenoma (NA) is uncommon in the pediatric population. It was first described in 1950 . Incidence is highest in middle-aged males , although pediatric patients are more commonly female . To our knowledge, this is the first reported case of nephrogenic adenoma in a patient with prune belly syndrome.
The reactive and metaplastic nature of the lesion is supported by its frequent occurrence with prior trauma to the urothelium, such as surgery, infection, calculi, and renal transplantation [1, 4]. Prune belly syndrome may increase the risk of NA, given that NA is associated with lower urinary tract changes, including dysfunctional voiding and recurrent UTI, and the need for reconstructive urologic surgery, as in our patient [5, 6]. Although traditionally thought to arise from urothelial metaplasia , research suggests that NA’s arise from exfoliated distal renal tubule cells [7, 8], which implant at sites of urothelial injury  with a histology resembling primitive renal collecting tubules. As a result, patients with both renal injury and bladder injury may have an increased risk of NA , and the hydroureteronephrosis and vesicoureteral reflux associated with prune belly syndrome may have increased our patient’s risk.
Common presenting symptoms include dysuria and hematuria, which tend to resolve after treatment. Recurrences are common. Heidenreich et al. report an 80% recurrence rate in children, with peak recurrence at approximately 4 years after treatment . Malignancy arising from NA has also been described in the adult literature, although no pediatric cases have been reported [4, 9, 10]. As a result, we recommend treatment with transurethral fulguration or resection and follow up with routine surveillance cystoscopy to confirm the absence of residual or recurrent lesions, despite the potential risk of recurrence from repeated instrumentation.
Nephrogenic adenoma is a rare papillary lesion of the bladder associated with urothelial injury. Due to its nonspecific presentation, the practitioner’s index of suspicion should be high in patients with irritative voiding symptoms and risk factors for urothelial disruption. Treatment with resection or fulguration may alleviate symptoms. Thus we advise that patients undergo routine surveillance until the etiology and malignant potential of nephrogenic adenoma are better elucidated. We recommend surveillence cystoscopy on a regimen similar to that used in superficial bladder cancer with initial evaluation every 3 months, with subsequent bi-annual and annual surveillance in asymptomatic patients. In patients with recurrent symptoms or other clinical indications, we recommend more frequent surveillance.