A Case of Primary Retroperitoneal Synovial Sarcoma

We have experienced a case of huge synovial sarcoma of the retroperitoneum which was successfully resected. A 55-year-old woman who had been noticed of a lower abdominal tumor since around 1995 was referred to the hospital with a suspicion of retroperitoneal tumor in January, 1997. After admission, abdominal CT scan and magnetic resonance imaging (MRI) revealed that the tumor was persent in the left retroperitoneum and rolled up from the aorta to left iliac artery about 13cm in length, and that the left kidney revealed hydronephrosis. Angiography showed that the tumor was poor in vascularity. CT guided needle biopsy presented a possibility of malignant tumor. A laparotomy performed on March 17 revealed that the tumor about 14×9cm in size was present in the retroperitoneum and rolled up the left hilum of kidney and ureter. An extirpation of the tumor except a small part of it which was left intact and a left nephrectomy were conducted. Histopathologically, the resected tumor was multilocular with a collection of a dark red fluid in it. Tumor cells in the solid part were of short spindle. The diagnosis of synovial sarcoma of the retroperitoneum was made. Infiltration of tumor cells was confirmed in the left renal pelvis and ureter. Postoperative course was uneventful and the patient is followed on an ambulant basis.