Bladder Urothelial Carcinoma Diagnosed by Perineal Cutaneous Biopsy: A Case Report

Bladder cancer is the most common malignancy of the urinary tract, and urothelial carcinoma represents its most frequent histological subtype in Brazil.Diagnosis is conventionally established by direct biopsy of the urothelial mucosa obtained through cystoscopy with transurethral resection of the bladder tumor, which also allows sampling of the detrusor muscle for adequate staging.We report the case of a 71-year-old hypertensive man without a smoking history who initially presented with perineal induration, difficulty in defecation, and intermittent diarrhea, and was first investigated for suspected inflammatory bowel disease.After an inconclusive colonoscopy, pelvic magnetic resonance imaging demonstrated bladder wall thickening with a right inferoposterior lesion measuring up to 3.7 cm, of probable neoplastic origin, extending toward the ureteral meatus, with bilateral upstream ureteropyelocaliceal dilation and contiguity with the prostate, corresponding to Vesical Imaging-Reporting and Data System (VI-RADS) category 5. On flexible ureteroscopy, the bladder lesion was directly visualized as a necrotic area consistent with tumor; transurethral resection could not be completed because perineal induration prevented advancement of the rigid instrument.Biopsies of the bladder and urethral mucosa were obtained with the flexible ureteroscope, together with an open incisional biopsy of the perineal skin.Histopathology of the bladder and urethral specimens showed only nonspecific chronic cystitis and urethritis, whereas the perineal skin specimen confirmed invasive urothelial carcinoma, with immunohistochemical positivity for GATA-binding protein 3 (GATA3) and cytokeratin 7 (CK7).The patient was later readmitted with postrenal acute kidney injury due to tumor invasion of the ureteral meatus, progressing to severe obstructive uropathy, and the disease had a fatal outcome despite bilateral nephrostomy and antibiotic therapy.This case illustrates cutaneous perineal biopsy as an unconventional but decisive diagnostic route when standard transurethral sampling is unfeasible or inconclusive.