CASE REPORT
Primary Synovial Sarcoma of the Kidney Shiu-Dong Chung,1,2 Kuo-How Huang,2 Shih-Chieh Chueh,2 Ming-Kuen Lai,2 Wei-Chou Lin3* Primary synovial sarcoma arising from the kidney is extremely rare. We report two cases with primary renal synovial sarcoma. Both were initially diagnosed as renal cell carcinoma. The first case was a 30-yearold woman who presented with right flank soreness. Ultrasonography disclosed a multiloculated cystic tumor measuring 9 × 7 cm. She underwent hand-assisted laparoscopic radical nephrectomy; there was no recurrence during 15 months of follow-up. The second case was a 49-year-old woman who presented with a palpable mass in the left upper quadrant of the abdomen of 1 month’s duration. Computed tomography showed a heterogeneously enhanced tumor measuring 13 × 11 cm at the left retroperitoneum with displacement of the pancreas and the left kidney. Hand-assisted retroperitoneoscopic radical nephrectomy was performed. She had no evidence of recurrence after 27 months of follow-up. Pathology of the two cases showed histologic and immunochemical features of synovial sarcoma with coexisting spindle and epithelial cells. Physicians should be aware of the possibility of malignancy in cystic renal masses and that synovial sarcoma is one of the possibilities. [J Formos Med Assoc 2008;107(4):344–347] Key Words: kidney, neoplasm, synovial sarcoma
Synovial sarcoma, a rare type of soft-tissue sarcoma, occurs primarily in the extremities in young adults. Primary synovial sarcoma arising from the kidney is extremely rare.1 The signs and symptoms are similar to any primary renal cancer, such as flank pain or hematuria. Diagnosis is clinically difficult through general survey or multiple imaging modalities. Pathologic confirmation always needs immunohistochemical stain or cytogenetic study. We describe two cases of primary renal synovial sarcoma that were treated successfully by hand-assisted laparoscopic radical nephrectomy. The relevant literature is also reviewed.
was unremarkable. Physical examination did not reveal any palpable lymph nodes or abdominal mass. Ultrasound revealed a well-defined and multiloculated cyst over the right kidney (Figure 1A). Computed tomography (CT) showed a low density perirenal mass, 9 × 7 × 6 cm in size. The tumor had focal hypervascular components and markedly compressed the right kidney (Figure 1B). No local invasion or lymphadenopathy was identified. Blood hemogram and biochemistry data were within normal limits. No venous thrombus was noted on angiography. The patient underwent hand-assisted laparoscopic radical nephrectomy under the presumed diagnosis of right renal cell carcinoma. Grossly, a well-defined cystic tumor that contained numerous papillary structures arising from a thick and fibrous wall was noted. The cut surface of the mass was whitish tan and firm with focal hemorrhage and necrosis. Histologic examination
Case Reports Case 1 A 30-year-old woman presented with a 1-month history of right flank soreness. Her medical history
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1
Department of Urology, Far Eastern Memorial Hospital, Ban Ciao, and Departments of 2Urology and 3Pathology, National Taiwan University Hospital, Taipei, Taiwan. Received: January 29, 2007 Revised: February 15, 2007 Accepted: August 7, 2007
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*Correspondence to: Dr Wei-Chou Lin, Department of Pathology, National Taiwan University Hospital, 7 Chung Shan South Road, Taipei, Taiwan. E-mail:
[email protected]
J Formos Med Assoc | 2008 • Vol 107 • No 4
Primary renal synovial sarcoma
A
B
Figure 1. (A) Ultrasonography shows a well-defined and multiloculated cystic tumor over the right kidney. (B) Computed tomography shows a low density perirenal mass, 9 × 7 cm, with marked compression of the right kidney.
A
B
Figure 2. (A) Plump, monomorphic neoplastic spindle cells with ovoid vesicular nuclei and indistinct cell borders (hematoxylin & eosin, 400×). (B) Epithelial tumor cells exhibiting a hobnail appearance with eosinophilic cytoplasm (hematoxylin & eosin, 400×).
showed synovial sarcoma composed of both epithelial cell and spindle cell components. The epithelial cell component exhibited ovoid nuclei with abundant cytoplasm arranged in a papillary structure. The spindle cell component demonstrated uniform cells with scanty cytoplasm and ovoid vesicular nucleoli arranged in a solid and fascicular pattern (Figure 2A). Immunohistochemical findings are listed in the Table. Chromosome translocation of t(X;18) was confirmed with reverse transcription–polymerase chain reaction (RT-PCR) and SYT-SSX1 fusion was detected. The primer sequences were as follows: SYT-α, 5′-AGA CCA ACA CAG CCT GGA CCA-3′; SSX-α, 5′-TGC TAT GCA CCT GAT GACGA-3′. The postoperative course was uneventful. There was no evidence of recurrence at the 15-month follow-up. J Formos Med Assoc | 2008 • Vol 107 • No 4
Case 2 A 49-year-old woman presented with a palpable mass in the left upper quadrant of the abdomen of 1 month’s duration. She was asymptomatic and denied other systemic disease. CT scan showed a heterogeneously enhanced tumor (13 × 11 cm in diameter) in the left retroperitoneum with displacement of the pancreas and left kidney. Left renal cell carcinoma was suspected. Bone scan and chest X-ray revealed no evidence of metastasis. Angiography of the left renal artery showed a huge mass at the inferior portion of the left kidney. There were relatively hypervascular components at the upper portion and a large poorly enhanced area at the lower portion. Transarterial embolization of the inferior branch of the renal artery was done. Laparoscopic retroperitoneoscopic radical nephrectomy was then 345
S.D. Chung, et al
Table. Clinical and immunohistochemical data of the two cases Age (yr)/Sex
Tumor size (cm)
Case 1
30/F
9×7×6
Case 2
49/F
13 × 11 × 8
Component Epithelial Spindle Epithelial Spindle
Bcl-2
CK
EMA
Vimentin
CD99
WT-1
Focal (+) − Focal (+) −
+ − + −
+ − + Focal (+)
+ + + +
Focal (+) − Focal (+) −
NA NA − −
CK = cytokeratin (monoclonal, 1:50; Dako); EMA = epithelial membrane antigen (monoclonal, 1:200; Dako); Vimentin = vimentin (monoclonal, 1:200; Dako); CD99 = CD99 (monoclonal, 1:50; Dako); WT-1 = Wilms’ tumor gene protein (monoclonal, 1:200; Santa Cruz Biotechnology Inc.); NA = not available.
performed. Grossly, there was a huge fragile cystic tumor measuring 13 × 11 × 8 cm in size around the lower pole of the kidney and mainly occupying the perirenal space. On section, the tumor was white and soft with extensive hemorrhage and necrosis. Microscopic examination showed biphasic cellular components. Tumor cells originating from stroma formed intersecting fascicles with ovoid to fusiform nuclei, coarse chromatin, variablesized nucleoli and frequent mitoses. Focal cystic areas lined by epithelial cells with acidophilic cytoplasm and a hobnail morphology were also discernible in the tumor (Figure 2B). The results of immunohistochemical staining are listed in the Table. SYT-SSX1 fusion transcripts were proved by RT-PCR with the same primer sequences as in Case 1. The patient had no evidence of recurrence at the 27-month follow-up.
Discussion Primary renal sarcomas are rare; leiomyosarcoma accounts for 40–60% of renal sarcomas, followed by liposarcoma, rhabdomyosarcoma and fibrosarcoma.1–3 Synovial sarcoma originating from the kidney is extremely rare and the histogenesis is uncertain. It was first described by Argani et al in 2000.1 Fewer than 30 patients have been described in the English literature.1–10 It affects young individuals of both genders. In a review of 19 case reports, the average age was 38.5 years and male predominance was noted with a male-to-female ratio of 1.7:1.4 Differentiating renal synovial sarcoma from adult Wilms’ tumor, clear-cell sarcoma of the kidney, primitive neuroendocrine tumor of the kidney, 346
and sarcomatoid renal cell carcinoma remains difficult.5–8 Histologically, primary renal synovial sarcomas consist of plump spindle cells with minimal cytoplasm, active mitotic figures and tubular cells. Cysts are commonly present and are lined with epithelial cells that possess eosinophilic cytoplasm with apical nuclei that create a hobnail appearance.8 Most cases reported are monophasic synovial sarcoma of the kidney. Our two cases were composed of spindle and epithelial cells. In previous case reports, ultrasonographic findings were never described. Through these cases, we demonstrated that synovial sarcoma of the kidney appears on ultrasound as a multiloculated cystic lesion. In addition, focal hypervascularity on enhanced abdominal CT was also noted. Venous thrombus cannot be regarded as a clue as renal cell carcinoma due to an exceptional renal synovial sarcoma could present with extended thrombus of the inferior vena cava and right antrium.3 In general, there are no clinical or imaging characteristics that can aid definitive preoperative diagnosis. The diagnosis always requires pathologic confirmation. Synovial sarcomas usually stain positively for cytokeratin, vimentin, bcl-2, and epithelial membrane antigen. Immunohistochemically, our two cases were completely negative for WT-1, completely negative for cytokeratin in spindle cells, mainly negative for O13 and focally positive for EMA and bcl-2 in spindle cells. Therefore, Wilms’ tumor, primitive neuroendocrine tumor of the kidney, and sarcomatoid renal cell carcinoma were unlikely (Table). The morphology observed in our cases and the age of these patients also made clear cell sarcoma and congenital mesoblastic nephroma unlikely. Molecular or cytogenic analysis was used J Formos Med Assoc | 2008 • Vol 107 • No 4
Primary renal synovial sarcoma
to confirm the pathologic diagnosis. In the study published by Argani et al, four cases showed the presence of the SS18/SSX2 fusion gene transcript and one case of the SS18/SSX1.1 In addition, a reciprocal translocation, t(X;18)(p11.2:q11.2), has been shown to be specific for synovial sarcoma.10 The prognosis of primary renal synovial sarcoma is unclear due to the limited number of reported cases. From previously published data, renal synovial sarcomas are believed to have aggressive clinical courses and poor outcomes.9,10 Surgical resection and ifosfamide-based chemotherapy are the mainstay for the management of renal synovial sarcoma.5 One case reported by Schaal et al demonstrated response to a regimen using ifosfamide and adriamycin.9 The monophasic tumor tends to have a better prognosis than the tumor with spindle and epithelial cells. Unlike previously reported cases who underwent open radical nephrectomy, our two patients received handassisted laparoscopic radical nephrectomy. Longterm follow-up will be required to determine prognosis, although short-term recurrence-free survival was observed. However, in managing cystic renal mass, extreme care must be taken to avoid inadvertent cyst puncture during tumor mobilization or excision. An adequate margin of normal parenchyma must be maintained.11 In conclusion, renal synovial sarcoma is rare and commonly affects young adults. Physicians should be aware of the possibility of malignancy in cystic renal masses and raise the suspicion of synovial sarcoma, especially when a young adult presents with a multiloculated cystic renal tumor on ultrasound. Minimally invasive hand-assisted
J Formos Med Assoc | 2008 • Vol 107 • No 4
laparoscopic radical nephrectomy is an alternative treatment for large-sized renal synovial sarcoma.
References 1. Argani P, Faria PA, Epstein JI, et al. Primary renal synovial sarcoma: molecular and morphologic delineation of an entity previously included among embryonal sarcomas of the kidney. Am J Surg Pathol 2000;24:1087–96. 2. Bella AJ, Winquist EW, Perlman EJ. Primary synovial sarcoma of the kidney diagnosed by molecular detection of SYT-SSX fusion transcripts. J Urol 2002;168:1092–3. 3. Chen PC, Chang YH, Yen CC, et al. Primary renal synovial sarcoma with inferior vena cava and right atrium invasion. Int J Urol 2003;10:657–60. 4. Chen S, Bhuiya T, Liatsikos EN, et al. Primary synovial sarcoma of the kidney: a case report with literature review. Int J Surg Pathol 2001;9:335–9. 5. Kampe CE, Rosen G, Eilber F, et al. Synovial sarcoma. A study of intensive chemotherapy in 14 patients with localized disease. Cancer 1993;72:2161–9. 6. Kim DH, Sohn JH, Lee MC, et al. Primary synovial sarcoma of the kidney. Am J Surg Pathol 2000;24:1097–104. 7. Koyama S, Morimitsu Y, Morokuma F, et al. Primary synovial sarcoma of the kidney: report of a case confirmed by molecular detection of the SYT-SSX2 fusion transcripts. Pathol Int 2001;51:385–91. 8. Perlmutter AE, Saunders SE, Zaslau S, et al. Primary synovial sarcoma of the kidney. Int J Urol 2005;12:760–2. 9. Schaal CH, Navarro FC, Moraes Neto FA. Primary renal sarcoma with morphologic and immunohistochemical aspects compatible with synovial sarcoma. Int Braz J Urol 2004; 30:210–3. 10. Shannon BA, Murch A, Cohen RJ. Primary renal synovial sarcoma confirmed by cytogenetic analysis: a lesion distinct from sarcomatoid renal cell carcinoma. Arch Pathol Lab Med 2005;129:238–40. 11. Spaliviero M, Herts BR, Magi-Galluzzi C, et al. Laparoscopic partial nephrectomy for cystic mass. J Urol 2005; 174:614–9.
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