This case report focuses on a patient who developed a panurethral stricture after receiving an immune checkpoint inhibitor and underwent urethral balloon dilatation surgery.

A 56-year-old male was diagnosed with high-grade left renal pelvic infiltrating urothelial carcinoma, stage IV, and low-grade papillary non-muscle invasive bladder cancer, stage 0a in September 2022. He underwent neoadjuvant chemotherapy with Gemcitabine and cisplatin and subsequent surgical interventions in January 2023. He was later diagnosed with high-grade infiltrating urothelial carcinoma of the left ureter, stage III, received radiotherapy from March to April 2023, with a total dose of 5040 cGy divided into 28 fractions, and continued outpatient follow-up. In January 2024, his IPSS score was 12 points, indicating moderate symptoms. On January 17, 2024, a follow-up cystoscopy revealed a tumor at the left bladder neck, leading to a transurethral bladder tumor resection. The pathology confirmed the recurrence of high-grade infiltrating urothelial carcinoma, and he received chemotherapy and nivolumab from February to May 2024. In August 2024, he presented with lower limb edema and an increased IPSS score of 21 points. He visited the emergency department in early September 2024 due to acute urinary retention, with a tentative diagnosis of panurethral stricture causing acute kidney injury. Emergency hemodialysis and cystoscopy with urinary catheterization were performed, followed by urethral balloon dilatation. After three weeks, the patient was hospitalized again due to acute urinary retention recurred on the day of catheter removal. After discussion with the patient, the decision was made to proceed with suprapubic tube cystostomy.

Immunotherapy may adversely affect the lower urinary tract. This report presents the inaugural case of immunotherapy-induced urethral stricture. The proposed pathogenic mechanism involves T cell activation and cytokine release, leading to inflammation and urothelial damage. This inflammation can hinder proper tissue repair, resulting in fibrosis and strictures. Surgical intervention remains the principal strategy for panurethral stricture, employing techniques such as the Kulkarni Technique and urethroplasty. In this instance, we utilized an innovative balloon dilation method as a less invasive surgical option for patients with panurethral stricture.

Based on the treatments the patient in this case had received, the possible causes of panurethral stricture include chemotherapy, radiotherapy, immunotherapy, and even cystoscopy and catheterization. Strictures caused by chemotherapy are a possible factor, particularly for drugs excreted in the urine, such as bleomycin. The drug-induced inflammatory cascade can lead to urethral fibrosis and subsequent stricture formation. Radiotherapy for prostate cancer patients often causes urethral stricture as a side effect, although the patient's urethra in this case did not receive radiotherapy. Because radiation injury is progressive and the rate of stenosis increases over time, long-term follow-up of patients treated with radiation therapy is warranted. Instances of immunotherapy-related cases have been documented, which may induce adverse effects on the lower urinary tract, including urethritis and cystitis. This case report delineates the first documented instance of immunotherapy leading to the development of urethral stricture. It is postulated that the underlying pathogenic mechanism involves the infiltration of activated T cells into the urothelium and subepithelial tissues, accompanied by the release of pro-inflammatory cytokines, culminating in inflammation and degradation of the urothelial barrier and adjacent tissues. Subsequent to the initial inflammatory phase, the compromised urethral tissues engage in a reparative process that, when dysregulated, precipitates pathological fibrosis and the eventual formation of strictures. The main treatment for urethral stricture is surgery, including Kulkarni Technique, dorsal onlay buccal mucosal graft urethroplasty, staged urethroplasty, and perineal urethrostomy. However, in this case, we used a novel treatment with balloon dilation, hoping to provide patients with urethral stricture with the option of minimally invasive surgery.