Ectopic ossification is a pathological condition in which bone formation abnormally occurs in soft tissues where bone is not normally present. It can develop following trauma, surgery, or fractures, with osteoblast-mediated bone formation typically occurring 2 to 8 weeks post-injury. We report a case of ectopic ossification after total nephroureterectomy.

The patient is a man in his 60s. He underwent total left nephroureterectomy with a diagnosis of left renal pelvis cancer.

Twenty days post-nephroureterectomy, the patient developed persistent left scrotal pain, initially suspected as epididymitis and treated with antibiotics. Nine months later, CT and radiographs revealed a newly developed 6 cm calcified pelvic lesion. Suspecting a retained foreign body, we performed laparoscopic resection, identifying and excising a bone-like structure near the internal inguinal ring and external iliac vein. Histopathology confirmed mature bone tissue without foreign material. Postoperatively, the pain resolved. Celecoxib was initiated on postoperative day 4, preventing recurrence for over a year. Mild intermittent scrotal pain persists but is controlled with tramadol/acetaminophen, which the patient had preoperatively for lumbar canal stenosis. CT shows no recurrence or metastasis.

We hypothesize that surgical trauma from the radical nephroureterectomy induced ectopic ossification, which subsequently compressed the genitofemoral nerve or its branches, leading to scrotal pain. A literature review revealed no previous reports of postoperative ossification occurring near the vas deferens, making this a rare and noteworthy case.