Synovial sarcoma is an extremely rare soft tissue cancer that predominantly affects young adults, typically occurring at the para-articular region of the extremities. Primary synovial sarcoma of the prostate is exceptionally uncommon in clinical practice.

Presented here is a case of a 29-year-old male with prostatic synovial sarcoma. He experienced lower urinary tract symptoms and eventually had urine retention. Also discussed here are the imaging findings, treatment plan, and differential diagnosis.

The patient experienced urinary frequency, dysuria, and acute urinary retention, which led to the insertion of a Foley catheter. Subsequent ultrasound scans revealed a large lobulated solid prostate gland. A prostate biopsy confirmed the presence of a malignant spindle cell neoplasm, indicating a prostatic stromal sarcoma. Immunohistomorphologic findings (TLE-1+, STAT6-, S100-, CD34-, ER-, PR-) were consistent with a diagnosis of Monophasic Synovial Sarcoma. The patient underwent six cycles of neoadjuvant chemotherapy before a Radical Prostatectomy was performed. The postoperative course was uneventful, and the patient was discharged in a significantly improved condition.

Given the rarity of this condition, the authors are reporting a case of prostatic synovial sarcoma and how they managed it. They performed a radical prostatectomy with neoadjuvant chemotherapy, which had a positive effect. Subsequent postoperative monitoring and imaging showed no further symptoms.