Pelvic heterotopic ossification causing bladder compression: a rare post-traumatic case report.

Introduction: Heterotopic ossification (HO) is the pathological formation of bone within soft tissues, most commonly following trauma or surgery. Pelvic HO that causes direct mechanical compression of the urinary bladder is exceptionally rare. We present a case that remained asymptomatic for over a decade before causing significant lower urinary tract symptoms. Case presentation: A 30-year-old man presented with a 4-month history of dysuria, gross hematuria, and left testicular pain, more than 10 years after a high-energy pelvic fracture. Multimodal imaging revealed an exophytic ossified mass arising from the left pubic ramus and compressing the lateral bladder wall. Histopathology confirmed benign submucosal ossification. Surgical excision achieved complete symptom resolution by postoperative day 10. Clinical discussion: This case illustrates the capacity of traumatic HO to remain clinically silent for years before causing organ compression, with radiological overlap among neoplastic and inflammatory conditions complicating diagnosis. A multidisciplinary orthopedic-urology approach is essential. Conclusion: Pelvic HO with bladder compression should be included in the differential diagnosis of bladder masses in patients with a remote history of pelvic trauma. Early recognition and surgical excision restore urinary function.