A 32 year-old woman was admitted due to intermittent abdominal pain which had persisted for one month. She had neither any remarkable past medical history nor family history. On physical examination, there was tenderness on the left upper quadrant of the abdomen; however, there was no palpable mass in the abdomen or no tenderness in both costovertebral angles. Laboratory data revealed that the lactate dehydrogenase (LDH) had risen to 1,114 IU/L. The others were within normal limits. Chest plain film showed streaky radiopaque densities on the right upper lobe, considered a scar of the inactive tuberculosis. Abdominal ultrasonogram showed a well-defined mixed echogenic mass on the left kidney. Abdominal computed tomography (CT) scan showed a well-defined mass with heterogenous enhancement on the lower pole of the left kidney with hilar infiltration, measured to be 12x10 cm in size (Figure 1). Small-sized hilar lymph nodes and a thrombus in the left renal vein were observed. On day 23, a left radical nephrectomy was performed with left renal vein thrombectomy. A gross specimen was obtained from the left kidney of the patient, a 13x12x11 cm-sized mass on the lower pole of the kidney. The cut surface of the mass was grayish-white mixed with focal necrosis and hemorrhage (Figure 2).
A light microscopic finding revealed a highly cellular tumor composed of mitotically active (to the degree about 30 mitoses/10 high power field), atypical plump spindle cells, and indistinct cell borders arranged in short and intersecting fascicles, mainly involving the renal pelvis with extension to the renal cortex and capsule (Figure 3). Malignant cells were not found in the dissected lymph nodes or in the renal vein.
On immunohistochemical stains, the tumor cells showed positive reaction to vimentin (Figure 4), but showed negative reactions to cytokeratin, epithelial membrane Antigen (EMA), S-100 protein, and CD34. There were no extrarenal manifestations, and we diagnosed the tumor as spindle cell-type monophasic synovial sarcoma, which had originated from the kidney.
Four months later, chest radiography showed a number of small nodular opacities considered as hematogenous metastasis. Chest CT scan showed variable sized, nodular opacities with vascular connection in the entire lobe of the right lung (Figure 5). Percutaneous transthorasic needle biopsy (PTNB) on the right lower lung nodule was performed, and the pathologic finding was consistent with renal synovial sarcoma (Figure 6). She had received combination chemotherapy with 28-day cycles of ifosfamide 2,500 mg/m2 on day 1 through 3 plus doxorubicin 60 mg/m2 on day 1. After the second cycle of chemotherapy, follow-up chest CT scan showed smaller-sized metastatic nodules on the right lung field, and the state of the response was partial remission. Toxicity was scored according NCl criteria. During chemotherpay, grade 2 neutropenia and grade 1 thrombocytopenia was developed. Non-hematologic toxocities were grade 1 nausea and grade 3 alopecia. Planed doses were administered without dose reduction. After 6 cycles of chemotherapy, complete remission was achieved (Figure 7).
Chest CT scan shows hematogenous dissemination of variable sized, multiple nodular opacities with vascular connection in the entire lobe of the right lung.