Nephrogenic Adenoma of the Urinary Bladder

Rare cause of macroscopic hematuria in a pediatric patient: nephrogenic adenoma of the bladder

Pediatric nephrogenic adenoma (NA) is an uncommon benign metaplastic lesion occurring in the urothelium. Herein we report a case of NA of the urinary bladder in a 14-year-old boy. The patient presented with macroscopic hematuria and had a history of ureteral surgery and long-term smoking. NA should be considered in the differential diagnosis of any urinary tract tumor in the pediatric population.

Renal and urologic disorders in antiretroviral-treated patients with HIV infection or AIDS: spectrum of cross-sectional imaging findings

In the aging human immunodeficiency virus (HIV)-infected population with improved immune function under antiretroviral treatment, many different opportunistic disorders may be encountered, along with rare presentations or complicated forms of common diseases. Renal and urologic abnormalities observed in the setting of HIV infection or acquired immunodeficiency syndrome are reviewed with their imaging appearances, including renal dysfunction, urolithiasis, urinary tract infections and related complications, genitourinary tuberculosis, vascular lesions, urogenital tumors, and bladder abnormalities, with emphasis on characterization. In HIV-positive patients, early cross-sectional imaging is warranted to detect uncommon disorders and complications, with the aim to preserve renal function.

Benign Diseases of the Bladder

Benign diseases of the bladder often present diagnostic challenges to practicing pathologists due to their diverse nature and ability to mimic a variety of epithelial or mesenchymal neoplasms. Categories of benign bladder disease include infectious cystitis, noninfectious cystitis, reactive proliferative processes, and benign processes that secondarily involve the bladder. An understanding of the key clinical and morphologic features of these lesions and the useful ancillary techniques specific for these entities is critical to the correct diagnosis of these lesions. This article reviews the key features of these benign bladder diseases and highlights methods to distinguish these lesions from other benign and malignant processes involving the bladder.

Fibromyxoid Nephrogenic Adenoma: A Newly Recognized Variant Mimicking Mucinous Adenocarcinoma

Nephrogenic adenomas demonstrate a variety of morphologic patterns that may occasionally be confused with malignant processes, including urothelial and prostatic carcinoma. In this series, we describe 8 cases of nephrogenic adenoma that contain an admixture of the classic tubular form of nephrogenic adenoma and an unusual spindled and fibromyxoid form of nephrogenic adenoma that closely mimics infiltrating carcinoma. In all cases, the classic tubular form of nephrogenic adenoma composed only a small proportion of the lesion, whereas the remainder consisted of compressed spindled cells within a fibromyxoid background, with only rare tubular and cordlike structures. On close examination, minimal nuclear atypia was identified in 2 cases, which included small, pinpoint nucleoli, and nuclear pseudoinclusions. All 8 patients were elderly men who had a prior or concurrent history of acinar prostate cancer (n=4), combined acinar prostate and urothelial carcinoma (n=1), urothelial-type adenocarcinoma of the prostate (n=1), bladder urothelial carcinoma (n=1), or no prior reported prostatic or urothelial abnormalities (n=1). Five patients received prior treatment with radiotherapy, 1 patient received intravesical mitomycin-C, and 1 also received bacillus Calmette-Guerin. The epithelial component of the lesions was positive in all cases for pancytokeratin (AE1/3) and racemase and demonstrated a variable cuff of type IV collagen surrounding the tubules. PAX-2 was positive with variable extent of labeling. Immunostains for prostate-specific antigen were negative. Histochemical stains identified some of the background matrix as mucin, with intense staining for periodic acid-Schiff and focal staining for mucicarmine. Stains for reticulin and amyloid (Congo red stain) and immunohistochemistry for Tamm-Horsfall protein were negative. This case series is the first report of a fibromyxoid subtype of nephrogenic adenoma. Awareness of this entity and the use of ancillary techniques can aid in the diagnosis of this unusual form of nephrogenic adenoma.