Bladder tumors in patients initially diagnosed with interstitial cystitis: a ten-year retrospective study

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic inflammatory condition characterized by bladder pain and lower urinary tract symptoms. As a diagnosis of exclusion, IC/BPS shares overlapping features with bladder tumors, which may lead to misdiagnosis or delayed diagnosis. Clinical evidence regarding the relationship between IC/BPS and bladder tumors remains limited.

In this single-center retrospective study, 863 patients initially diagnosed with IC/BPS who underwent cystoscopic hydrodistension with random multi-site bladder biopsies between January 2015 and June 2025 were reviewed. Twenty-five patients who were subsequently diagnosed with bladder cancer or nephrogenic adenoma based on initial or repeated biopsies were included. Clinical, imaging, cystoscopic, pathological, treatment, and follow-up data were analyzed.

The cohort included 15 males and 10 females, with a median age of 56 years. The most common initial symptoms were urinary frequency, urgency, and dysuria. Hematuria developed in eight patients during disease progression. Imaging frequently showed bladder wall thickening without definite mass lesions. Cystoscopic findings were heterogeneous, ranging from diffuse inflammatory changes to tumor-like lesions. Fourteen patients were diagnosed at initial biopsy, while others were diagnosed after repeated biopsies. Twelve patients underwent radical cystectomy. During a median follow-up of 48 months, recurrence and metastasis rates were low. Oncologic outcomes should be interpreted cautiously because follow-up was incomplete and heterogeneous.

A subset of patients initially diagnosed with IC/BPS may harbor or develop bladder tumors. Close surveillance and repeated cystoscopic multi-site biopsies are recommended, particularly in high-risk patients such as males and those with hematuria, to improve early detection and outcomes.