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Year : 2021  |  Volume : 10  |  Issue : 2  |  Page : 112-115

Renal synovial sarcoma: A rare entity with a poor prognosis

1 Department of Urology, Sri Venkateswara Institute of medical sciences(SVIMS), Tirupati, Andhra Pradesh, India
2 Department of Urology, BYL Nair Hospital and Topiwala National Medical College, Mumbai, Maharashtra, India Where the work was carried out: Department of Urology, Sri Venkateswara Institute of medical sciences (SVIMS), Tirupati, Andhra Pradesh, India

Date of Submission14-Sep-2021
Date of Acceptance14-Oct-2021
Date of Web Publication20-Dec-2021

Correspondence Address:
Dr. Suraj Pinni
Department of Urology, BYL Nair Hospital and TNMC, Mumbai - 400008, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jdrntruhs.jdrntruhs_126_21

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Renal synovial sarcoma is a rare disease with less than 200 cases reported in the literature. A 36-year-old lady presented with hematuria and underwent radical nephrectomy for a left-sided renal synovial sarcoma. She developed lung metastasis and the disease progressed further despite of chemotherapy. Renal synovial sarcoma can be diagnosed by studying morphology and performing an Immuno-histochemistry (IHC) panel (Transducin-like enhancer of split (TLE); B Cell Lymphoma (BCL)-2; CD99) on resected tumor tissue. Molecular testing for t(x; 18)(p11.2;q11.2) translocation is considered the gold standard diagnostic test. The common presenting symptoms include hematuria, pain, or a palpable lump. The imaging modalities are not diagnostic and surgical resection is the treatment of choice at present. Due to the rarity of the disease, the treatment guidelines are not well-defined. Anthracyclines alone or in combination with Ifosfamide has been reported to be used in the literature in the adjuvant as well as metastatic settings. The overall prognosis is poor with a short median survival ranging from 6 to 24 months.

Keywords: Hypovascular renal masses, immunohistochemistry (IHC), renal synovial sarcoma

How to cite this article:
Nallabothula AK, Pinni S, Singh AK, Nasare VM. Renal synovial sarcoma: A rare entity with a poor prognosis. J NTR Univ Health Sci 2021;10:112-5

How to cite this URL:
Nallabothula AK, Pinni S, Singh AK, Nasare VM. Renal synovial sarcoma: A rare entity with a poor prognosis. J NTR Univ Health Sci [serial online] 2021 [cited 2023 Jan 27];10:112-5. Available from: https://www.jdrntruhs.org/text.asp?2021/10/2/112/332847

  Introduction Top

Synovial sarcomas account for 5–10% of the soft tissue sarcomas in adults, and out of these, the primary renal origin is even rarer.[1] Renal synovial sarcoma is a rare and aggressive sarcoma with fewer than 200 cases reported in available literature. Moreover, no well-defined treatment guidelines are available for its management to date.[2] Confirmation of the diagnosis requires IHC panel testing followed by molecular testing in almost all cases.[3] Here we present a case of renal synovial sarcoma in a young female who had presented with hematuria and had rapidly progressed to metastatic disease despite treatment and is presently receiving palliative treatment.

  Case History Top

A thirty-six-year-old woman presented to us with the primary complaint of a single episode of painless gross hematuria. Contrast-enhanced Computed Tomography (CT) of the abdomen was suggestive of a heterogeneous, poorly enhancing, hypovascular mass measuring 5 cm × 5 cm arising from the upper pole of the left kidney. The lesion was indenting adjacent pelvicalyceal system and had a few calcifications as well. Perinephric fat stranding was noted but there was no evidence of lymphadenopathy or renal vessel involvement [Figure 1]. The radiological differential diagnosis included malignant or an infective pathology. All laboratory investigations including serum creatinine, hemogram, and liver function tests were within normal limits. The chest X-ray showed normal lung and heart shadows. Renal mass biopsy was done under image guidance which showed spindle cells with pleomorphic nuclei and occasional mitotic figures confirming the diagnosis of a malignancy. IHC markers Friend Leukemia integration (FLI)-1 (nuclear) were faintly positive whereas CD-99 (membranous) and BCL-2 (nuclear) were diffusely positive in the tumor cells suggestive of a diagnosis of synovial sarcoma. Laparoscopic left radical nephrectomy was performed which included complete removal of the kidney along with Gerotas fascia, perinephric fat, proximal two-thirds of the ureter, and standard left-sided lymphadenectomy. The post-operative period was uneventful and the patient was discharged on day 5. The final histopathology report was suggestive of a tumor mass measuring 9.5 cm × 7 cm × 7 cm with focal hemorrhages and cystic changes [Figure 2]. The renal sinus and perinephric fat were found infiltrated. On microscopy, spindle cells with nuclear pleomorphism were found, arranged in rosettes, and a lobular arrangement with fibrous septae. Focal myxoid stroma was also detected. Mitotic figures were noted in 30 cells per 10 HPF. Lympho-vascular invasion was detected, but all the seven lymph nodes in the lymphadenectomy specimen were negative for tumor deposits. The resection margins were found to be negative. On the basis of IHC analysis (Pan CK and CD45 negativity with CD99 and TLE-1 positivity), a diagnosis of monophasic synovial sarcoma (Tumor, Node & Metastases (TNM) stage T2aN0M0) was made [Figure 3]. During the first follow-up at 2 weeks, the CT of the chest showed soft tissue densities in the bilateral lungs as well as retroperitoneal lymphadenopathy suggestive of metastasis. The patient received two cycles of Adriamycin monotherapy (60 mg/m2) followed by three cycles of Ifosfamide-Adriamycin (IA) regimen. Imaging for response assessment at 6 months showed disease progression with an increase in the size and number of lung metastasis in addition to new lytic vertebral (D9-D10) metastasis. The patient received palliative radiotherapy for bone metastasis and is on a follow-up at present.
Figure 1: Contrast-enhanced CT of the abdomen showing a heterogenous, hypovascular left renal mass involving the mid and upper pole (white arrow) with peripheral calcification (black arrow) and surrounding normal renal parenchyma (black arrowhead)

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Figure 2: Cut open (coronal) section of the left radical nephrectomy specimen showing the upper and mid pole mass with areas of hemorrhage and necrotic tissue

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Figure 3: Histopathology sections showing (a) plump spindle cells at 400X magnification (Hematoxylin and Eosin), (b) IHC-CD99: Showing diffuse membranous positivity in the lesional cell, (c) IHC-BCL2: Showing diffuse nuclear positivity in the lesional cells, and (d) IHC-BCL2: Showing faint nuclear positivity in the lesional cells

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  Discussion Top

Synovial sarcoma arising from the kidney is an extremely rare pathology with fewer than 200 cases reported in available literature.[2],[3],[4],[5],[6] This clinicopathologic entity was first described by Argani et al.[3] in 2000. They identified that a number of cases diagnosed as embryonal sarcomas of kidney (ESK) had a morphology similar to synovial sarcomas elsewhere in the body which was further confirmed by molecular testing. Synovial sarcomas can be morphologically categorized into monophasic (spindle cells), biphasic (spindle with epithelial cells), and poorly differentiated subtypes. Gene expression profiling with the help of IHC marker panel (TLE-1, BCL-2, CD99, FLI-1, PanCK), if positive, can confirm the diagnosis of synovial sarcoma with the pitfall that a negative marker panel does not rule it out. Molecular testing for t(x; 18)(p11.2;q11.2) translocation and its fusion product (SS18-SSX) can detect more than 90% of the synovial sarcomas.[6] Monophasic histologic type and the SS18-SSX2 fusion are the most common type found in renal synovial sarcomas.[2],[4],[5] Though molecular testing (Fluorescence in situ hybridization (FISH) or Reverse transcription Polymerase chain reaction (RT-PCR)) is considered the gold standard to diagnose renal synovial sarcoma, it can be done away with when the morphology and IHC (in particular TLE) is suggestive of synovial sarcoma.[7] In our case, molecular testing was not done due to practical issues related to the availability and cost, moreover, monophasic renal synovial sarcoma was proven beyond doubt on the IHC panel.

Renal synovial sarcoma is usually seen in young to middle-aged adults (20–50 years).[4] Both men and women are affected almost equally by this disease. The most common presenting complaints include hematuria, pain, or palpable mass.[2] Rarely, patients can present with a retroperitoneal bleed.[8] Imaging with contrast-enhanced CT, which is the standard for evaluating renal masses, can give some clues but is not diagnostic. The tumor may appear as a large mass with heterogeneous enhancement, hemorrhage, calcification, and air-fluid levels. A 'triple sign' might be visible on T2-weighted MRI scans.[5] In the present case, the CT demonstrated a hypovascular mass which raised the suspicion of an infective pathology, and hence, a percutaneous renal biopsy was performed. Zhang et al.[9] encountered a similar finding of a hypovascular renal mass which eventually turned out to be synovial sarcoma.

Surgical resection with radical nephrectomy is considered the treatment of choice at present. Due to the rarity of the disease, the role of chemotherapy in the adjuvant settings is not well-defined yet. Anthracyclines alone or in combination with Ifosfamide has been reported to be commonly used in the literature in the adjuvant as well as metastatic setting.[5] Renal synovial sarcomas are known to have early metastasis and tumor recurrences. The most common metastatic sites are lungs followed by retroperitoneum or abdominal nodes, liver, and bones. In a recent systematic review of 177 patients, the median survival with and without metastasis at diagnosis was found to be 6 and 37 months, respectively.[2] Several molecular-based studies are underway to understand better tumor biology and identify possible targets (TLE-1) for therapeutic interventions.[2],[4],[7]

In conclusion, renal synovial sarcoma is a rare and aggressive tumor which requires IHC and/or molecular testing to confirm the diagnosis. Imaging studies are inconclusive in diagnosing it correctly. The present therapeutic approaches have shown poor survival outcomes.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Grampurohit VU, Myageri A, Rao RV. Primary renal synovial sarcoma. Urol Ann 2011;3:110-3.  Back to cited text no. 1
[PUBMED]  [Full text]  
Blas L, Roberti J. Primary renal synovial sarcoma and clinical and pathological findings: A systematic review. Curr Urol Rep 2021;22:25.  Back to cited text no. 2
Argani P, Faria PA, Epstein JI, Reuter VE, Perlman EJ, Beckwith JB, 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.  Back to cited text no. 3
Schoolmeester JK, Cheville JC, Folpe AL. Synovial sarcoma of the kidney: A clinicopathologic, immunohistochemical, and molecular genetic study of 16 cases. Am J Surg Pathol 2014;38:60-5.  Back to cited text no. 4
Iacovelli R, Altavilla A, Ciardi A, Urbano F, Manai C, Gentile V, et al. Clinical and pathological features of primary renal synovial sarcoma: Analysis of 64 cases from 11 years of medical literature. BJU Int 2012;110:1449-54.  Back to cited text no. 5
Rose L, Grignon D, Cheng L, Fan R, Zhang S, Alruwaii F, et al. Primary renal synovial sarcomas: PAX 8 immunostaining and unusual molecular findings. Appl Immunohistochem Mol Morphol 2020;28:221-8.  Back to cited text no. 6
Terry J, Saito T, Subramanian S, Ruttan C, Antonescu CR, Goldblum JR, et al. TLE1 as a diagnostic immunohistochemical marker for synovial sarcoma emerging from gene expression profiling studies. Am J Surg Pathol 2007;31:240-6.  Back to cited text no. 7
Huned D, Kam JH, Lee LS, Tiwari RV. Primary renal synovial sarcoma presenting with a retroperitoneal bleed. BMJ Case Rep 2021;14:e237099.  Back to cited text no. 8
Zhang B, An C, Zhang Y, Tian J, Wang Z, Wang J. Primary renal synovial sarcoma: A case report. Medicine 2020;99:e22706.  Back to cited text no. 9


  [Figure 1], [Figure 2], [Figure 3]


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