Primary monophasic synovial sarcoma of the kidney: a case report and review of literature

Abstract

Primary synovial sarcoma (SS) of the kidney is a rare neoplasm and its presenting features are similar to other common renal tumors, making early diagnosis difficult. To date, few cases have been reported in the literature. Primary renal SSs can exist in either a monophasic or a biphasic pattern, the former being more common and tending to have a better prognosis than the biphasic variant. Herein we describe a case of primary renal SS that was diagnosed based on histopathology and immunohistochemistry after radical nephrectomy. Fusion gene product analysis was also done by FISH and RT-PCR. Patient follow-up and literature review are presented, focused on systemic therapy. We highlight that these tumors should be correctly diagnosed as clinical results and specific treatment are distinct from primary epithelial renal cell carcinoma. Adjuvant chemotherapy should be tailored for each patient in the management of disease, although its role still remains unclear.

Keywords: SYT-SSX fusion protein; chemotherapy; kidney neoplasms; synovial sarcoma.

Figure 1

Abdominal CT scan shows lower left renal mass (arterial phase).

Figure 2

Abdominal CT scan shows lower left renal mass (portal phase).

Figure 3

(A) Monomorphic neoplastic spindle cells mitotic activity (H & E, ×400). (B) Vimentin immunopositive cells (×400). (C) AE1/AE3 focal immunopositive cells (×400). (D) CD99 immunopositive cells (×400).