Nephrogenic Adenoma of the Urinary Bladder: A Review of the Literature

Abstract

Background. Nephrogenic adenoma of the urinary bladder (NAUB) is a rare lesion associated with nonspecific symptoms and could inadvertently be misdiagnosed. Aim. To review the literature. Methods. Various internet search engines were used. Results. NAUB is a benign tubular and papillary lesion of the bladder, is more common in men and adults, and has been associated with chronic inflammation/irritation, previous bladder surgery, diverticula, renal transplantation, and intravesical BCG; recurrences and malignant transformations have been reported. Differential diagnoses include clear cell adenocarcinoma, endocervicosis, papillary urothelial carcinoma, prostatic adenocarcinoma of bladder, and nested variant of urothelial carcinoma; most NAUBs have both surface papillary and submucosal tubular components; both the papillae and tubules tend to be lined by a single layer of mitotically inactive bland cells which have pale to clear cytoplasm. Diagnosis may be established by using immunohistochemistry (positive staining with racemase; PAX2; keratins stain positive with fibromyxoid variant), electron microscopy, DNA analysis, and cytological studies. Treatment. Endoscopic resection is the treatment but recurrences including sporadic malignant transformation have been reported. Conclusions. There is no consensus on best treatment. A multicentre study is required to identify the treatment that would reduce the recurrence rate, taking into consideration that intravesical BCG is associated with NAUB.

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

“…As nephrogenic adenomas are rare lesions, they can easily be confused and/or misdiagnosed as a variety of other malignant lesions of the urinary system. These can be associated with various inflammatory processes, to include: recurrent urinary tract infections, urinary calculi, prior renal transplants, bladder wall diverticulum, radiotherapy as well as chemical agents and other irritative therapies [5 , 7] .…”

“…Nephrogenic adenomas primarily occur in adults, with males 3 times more likely to have NA than women [4] . Ten percent of nephrogenic adenomas occur in children [5] . Reported cases of nephrogenic adenomas in children exclusively involve the bladder with the most frequent predisposing factor being reimplantation of the ureters for vesicoureteral reflux [6] .…”

Nephrogenic adenoma of the bladder: a single institution experience assessing clinical factors

“…Our study showed recurrence in five patients and Gordetsky's recent study found one in 31 patients with recurrence. Other studies had varying numbers of recurrence, but recommendations were made to have long term follow-up as recurrences were common ( 5 – 8 , 13 , 14 , 20 ). Given the symptomatic nature of this lesion and its tendency to recur, it would be prudent to follow patients with a cystoscopy and treat any of these recurrences.…”

Fibromyxoid Nephrogenic Adenoma in the Ureter

“…Follow-up studies have indicated that nephrogenic adenomas in the genitourinary tract can recur after resection but do not progress to carcinoma or metastasize. 4 Two case reports have described bladder tumors that appear to have undergone malignant transformation from nephrogenic adenoma to adenocarcinoma, underscoring the importance of continued follow-up for patients with nephrogenic adenoma. 4 …”

“… 4 Two case reports have described bladder tumors that appear to have undergone malignant transformation from nephrogenic adenoma to adenocarcinoma, underscoring the importance of continued follow-up for patients with nephrogenic adenoma. 4 …”