Periprostatic Abscess Extending to the Perineum Following Hydrogel Spacer Placement: A Case Report.

Introduction: Hydrogel spacers are commonly used to minimize rectal toxicity during prostate cancer radiotherapy. We report a case of a periprostatic abscess extending to the perineum following hydrogel spacer placement. Case Presentation: A 59-year-old man diagnosed with prostate cancer (serum prostate-specific antigen level, 6.71 ng/mL; Gleason score, 3 + 4; cT2aN0M0) underwent transperineal hydrogel spacer placement before stereotactic radiotherapy. Twenty-two days later, the patient developed urinary retention and painful perineal swelling. Computed tomography of pelvis revealed an abscess extending from the prostate to the perineum and scrotum. Broad-spectrum antibiotics were administered, followed by emergency perineal abscess drainage and percutaneous cystostomy. Residual abscesses required percutaneous drainage. The infection was cured, and the cystostomy successfully removed seven months after the onset of symptoms. Conclusion: Although rare, severe infectious complications can occur following hydrogel spacer placement. Careful patient selection and perioperative management are essential to reduce risk and ensure patient safety.