Primary Synovial sarcoma of the kidney: Unravelling a rare and aggressive tumor

This is the authors' abstract. We don't add key points for this paper.

Primary renal synovial sarcoma (PRSS) is an exceptionally rare and aggressive malignancy, comprising only 1–3% of all renal neoplasms. Its clinical and radiological features often mimic renal cell carcinoma, posing significant diagnostic challenges. This case report highlights a case of primary renal synovial sarcoma and reviews the relevant published literature. A 47-year-old male patient presented with right flank pain and hematuria. Contrast-enhanced CT revealed a heterogeneous right upper pole renal mass measuring 7.9 x 7.2 x 6.9 cm with necrosis and vascular involvement, raising suspicion for renal cell carcinoma. He underwent radical nephrectomy with thrombectomy. Histopathological examination showed a high-grade spindle cell tumor, infiltrating the perinephric fat, renal sinus, and adrenal gland. Immunohistochemistry was positive for TLE1, SS18::SSX fusion–specific antibody, CD99, BCL2 and Vimentin, confirming PRSS. Postoperative imaging revealed lung metastases, prompting initiation of ifosfamide and doxorubicin-based chemotherapy which was later modified to gemcitabine and docetaxel due to ifosfamide induced renal tubular acidosis. PRSS is an aggressive and diagnostically challenging entity that requires a multimodal approach, including histopathology, immunohistochemistry, and molecular testing, where available. Due to the lack of standardized treatment, further studies are essential to establish optimal therapeutic protocols and improve patient outcomes.