Diagnosis Of Synovial Sarcoma Research Articles

A review of the literature on synovial sarcoma of the kidney

Synovial cell sarcomas of the kidney are rare tumours that most urologists and pathologists throughout the world have not encountered. Because of this, most practitioners may not be aware of the presentation, diagnostic features or biological behaviour of such tumours. This article reviews the literature on synovial cell sarcomas of the kidney in order to document the presentation, investigation, management as well as outcome following treatment of these tumours. Synovial sarcoma of the kidney is a rare tumour that was first reported in 1999 and, since then, 64 cases have been reported in the literature. Synovial sarcomas of the kidney tend to be found in patients who are aged between 17 and 61 years, and the clinical presentation and radiography findings are similar to those of other renal tumours. There are three main types of primary synovial sarcomas of the kidney: the biphasic, the monophasic and the poorly differentiated varieties. Primary biphasic synovial sarcomas contain both glandular elements and spindle epithelial cells, whereas primary monophasic synovial sarcomas are composed of spindle cells only and poorly differentiated synovial sarcomas (PDSSs) exhibit three histological variants: large cell, small cell and high-grade spindle cell variant. PDSSs are composed of sheets of undifferentiated round cells with hyperchromatic nuclei and frequent mitoses, and such tumours are often associated with a rich vascular pattern with dilated and thin-walled vascular spaces that resemble haemangiopericytoma. The differential diagnoses include adult Wilms' tumour, transitional cell carcinoma, renal cell carcinoma, haemangiopericytoma, congenital ectoblastic nephroma and primitive neuroectodermal tumour (PNET).Diagnosis of renal synovial sarcoma is based on microscopic findings of (a) spindle cells (monophasic) or (b) glandular cells and spindle cells (biphasic) supported by immunohistochemical staining characteristics [positivity for CD99, CD56, Bcl-2, epithelial membrane antigen (EMA) and cytokeratin (CK)] and molecular genetic studies of the tumour showing characteristic chromosomal translocation t(X;18)(p11.2;q11.2), which is seen in cases of synovial sarcoma. There is no consensus regarding the treatment of synovial sarcoma of the kidney; however, surgical excision including a portion of surrounding normal tissue (radical nephrectomy) has so far been the main treatment. In addition, response to ifosfamide and doxorubicin (adriamycin) chemotherapy has been reported. Recurrence following treatment for non-metastatic synovial sarcoma is approximately 36% and prognosis for advanced disease is poor. Diagnosis of synovial sarcoma of the kidney is based upon characteristic microscopic findings that must be supported by specific diagnostic immunohistochemistry characteristics and molecular genetic evidence of chromosomal translocation. Because of the rarity of synovial sarcomas of the kidney, urologists and oncologists need to report all cases they encounter, together with reports of long periods of follow-up, to enable practitioners to fully understand the biological behaviour of such tumours.

Diagnostic utility of SOX10 to distinguish malignant peripheral nerve sheath tumor from synovial sarcoma, including intraneural synovial sarcoma

Synovial sarcoma and malignant peripheral nerve sheath tumor pose a significant diagnostic challenge given similar histomorphology. The distinction is further complicated by similar immunophenotype and especially by occasional synovial sarcomas that present as intraneural tumors. Although the presence of a t(X;18) rearrangement or expression of TLE1 can help confirm the diagnosis of synovial sarcoma, negative results for these tests are not diagnostic of malignant peripheral nerve sheath tumor. The SOX10 transcription factor, a putative marker of neural crest differentiation, may have diagnostic utility in this differential, but immunohistochemical data are limited. The goal of the present study was to determine the diagnostic utility of SOX10 to discriminate between synovial sarcoma and malignant peripheral nerve sheath tumor. Forty-eight cases of malignant peripheral nerve sheath tumor, all from patients with documented neurofibromatosis, and 97 cases of genetically confirmed synovial sarcoma, including 4 intraneural synovial sarcomas, were immunohistochemically stained for SOX10. The stain was scored for intensity and fraction of cells staining. Thirty-two of 48 malignant peripheral nerve sheath tumors (67%) were SOX10-positive. The majority of malignant peripheral nerve sheath tumors showed ≥2+ staining, but staining did not correlate with grade. By contrast, only 7/97 (7%) synovial sarcomas were SOX10-positive. Only three synovial sarcomas showed ≥2+ staining but, importantly, two of these were intraneural synovial sarcoma. Therefore, SOX10 is a specific (93%), albeit not very sensitive (67%), diagnostic marker to support a diagnosis of malignant peripheral nerve sheath tumor over synovial sarcoma. Furthermore, the stain needs to be interpreted with caution in intraneural tumors in order to avoid a potential diagnostic pitfall. It remains to be determined whether SOX10-positive cells in intraneural synovial sarcoma represent entrapped Schwann cells, synovial sarcoma cells or both.

A Patient with Primary Pericardial Synovial Sarcoma who Presented with Cardiac Tamponade: A Case Report and Review of the Literature

A 36-year-old man presented with near-syncope. He was found to have massive pericardial effusion with a giant pericardial tumorous lesion. The pericardial effusion exhibited a bloody nature; however, neither malignant cells nor infectious organisms were detected. (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) showed an increased uptake of FDG in the pericardial tumor only. Although the tumor was not resectable, thoracotomy and tissue sampling were performed. A histological analysis showed CD99 positivity and SYT gene rearrangement, leading to a diagnosis of synovial sarcoma arising from the left lateral pericardial surface. The patient is now receiving chemotherapy.

Application of immunohistochemistry in the diagnosis of small round blue-cell tumors of soft tissue.

Small round blue-cell tumors (SRBCTs) of soft tissue, which mainly include rhabdomyosarcoma (RMS), synovial sarcoma (SS), and Ewing's sarcoma/peripheral primitive neuroectodermal tumors (EWS/ pPNETs), are malignancies with overlapping morphological and immunohistochemical characteristics. Immunohistochemistry is one of the most prevalent and convenient methods for pathological diagnosis; however, differentiation between SRBCT subtypes in the absence of valid diagnostic markers is still very challenging. The purpose of the present study was to investigate diagnostic immunohistochemistry for subtyping soft tissue SRBCTs. Seventeen RMS, 25 SS, and 14 EWS/pPNETs were investigated. Reverse transcription RT-PCR and immunohistochemistry was performed to determine a diagnosis. Also, the expression of CD99, FLI1, PAX5, myogenin, and Keratin/EMA was assessed between subtypes. The sensitivity and specificity test was performed to evaluate their diagnostic significance. The sensitivity and specificity of the target markers were evaluated as follows. FLI1 and CD99 expression displayed strong associations in EWS/pPNETs, with OR (95% CI) and p values of 3.82 (1.23 - 11.94), p = 0.021 and 123.50 (12.63 - infinity), p < 0.001, respectively. Keratin/EMA expression did not support the diagnosis of EWS/pPNETs [OR (95% CI) = 0.06 (0.01 - 0.53), p = 0.011]. Myogenin expression displayed strong association with RMS, with high sensitivity and specificity of 94.1% and 100%, respectively. Membrane expression of CD99 did not support the diagnosis of RMS [OR (95% CI) = 0.09 (0.01 - 0.75), p = 0.026]. Keratin/EMA expression strongly indicated SS [OR (95% CI) = 345.00 (29.44 - infinity), p = 0.00011. A ROC curve value of 0.94 indicated that keratin/EMA expression might be a promising biomarker for SS, while separate expression of FLI1 and CD99 did not support the diagnosis of SS. Similarly, myogenin expression in RMS might be a promising biomarker for RMS with a ROC curve value of 0.97. Diagnosis of SRBCTs should be based on a comprehensive analysis involving morphology and immunoreactivity to a panel of markers.

Primary pericardial synovial sarcoma: A case report and literature review

Primary pericardial synovial sarcoma is extremely rare, with few published cases in the literature. We report the case of an adolescent aged 13 years with primary pericardial synovial sarcoma discovered during tamponade, confirmed by molecular biology, and for whom treatment combined radiosurgery and adjuvant chemotherapy. The particularity of the case we are reporting stems from the young age of our patient (13 years) as well as the duration of remission, which is quite long (21 months) prior to a superior mediastinal relapse compared to cases reported in the literature.<Learning objective: Synovial sarcoma is difficult to diagnose and has a poor prognosis. Here, a 13-year-old diagnosed with primary pericardial synovial sarcoma was treated with combined radiosurgery and adjuvant chemotherapy leading to continuous remission for 21 months. This regimen could be used to successfully manage future patients. Molecular biology is useful in the diagnosis of synovial sarcoma through the identification of t(X;18) translocation in atypical locations as in the present case.>

Reappraisal of TLE‐1 immunohistochemical staining and molecular detection of SS18‐SSX fusion transcripts for synovial sarcoma

The aim of the present study was to re-evaluate TLE-1 staining and the molecular detection methods of SS18-SSX transcripts for synovial sarcoma. We analyzed TLE-1 expression in 50 molecularly confirmed synovial sarcomas and 85 other soft tissue tumors with three previously published scoring systems. In the present study, 39 to 43 synovial sarcomas showed TLE-1 nuclear staining, whereas 9-15 of 85 other soft tissue tumors showed TLE-1 staining (P < 0.0001). The specificities of strong TLE-1 staining were 100%, 97.6% and 98.8%. The positive likelihood ratio of moderate and strong TLE-1 nuclear expression was >10 in all three scoring systems. There was no difference in TLE-1 staining between different subtypes of synovial sarcoma (P > 0.05). Based on a comparison between conventional reverse transcription (RT)-polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH), quantitative RT-PCR is a more sensitive method than conventional RT-PCR and FISH to detect t(X;18). A positive correlation between TLE-1 staining and SS18-SSX translocation was detected by conventional PCR (P < 0.05). In conclusion, although all three scoring systems could differentiate synovial sarcoma from other soft tissue tumors, diffuse moderate to severe intensity tumors showed the highest specificity in the diagnosis of synovial sarcoma.

A rare synovial sarcoma of the spine in the thoracic vertebral body

Synovial sarcomas of the spine are very rare, most rare of which was occurring in the thoracic vertebral body. The diagnosis of synovial sarcomas was very difficult. It depends on the radiological examination, immunohistochemical examination and gene examination. The best treatment to them was completely surgical resection with negative margins. Other treatments such as radiation therapy and chemotherapy were just adjuvant. The prognosis of synovial sarcomas was disappointing. A 26-year-old male patient had low back pain. The radiological examination showed bony erosion of the T7 vertebral body and no soft tissue mass around the spine. He underwent T7 resection en bloc and internal fixation with two levels above T7 and two levels below T7. Then histopathological and gene examination revealed high malignant synovial sarcoma. So he was treated by chemotherapy and external beam radiation therapy after surgery. Primary vertebral body synovial sarcoma is very rare and difficult to diagnose and treat.

Primary Pulmonary Synovial Sarcoma: A Rare Primary Pulmonary Tumor

Pulmonary sarcomas overall are very uncommon and comprise only 0.5% of all primary lung malignancies. The diagnosis is established only after sarcoma-like primary lung malignancies and a metastatic extrathoracic sarcoma have been excluded. Synovial sarcoma accounts for ~8% of soft-tissue sarcomas. Synovial sarcoma arising from the pleura has rarely been reported. We report a case of a 58-year-old woman who complained of right-sided chest pain and shortness of breath. Chest CT scan revealed a large heterogeneous mass, occupying most of the right hemithorax. Histologic diagnosis was supplemented by interphase cytogenetic (FISH) analysis. Computed tomography guided Tru-cut biopsy was suspicious for a sarcomatous or fibrous malignancy. However, intraoperative frozen-section diagnostics confirmed the diagnosis of a sarcoma. Immunohistochemistry showed that tumor cells expressed epithelial membrane antigen, CD99 and BCL2. Based on immunohistochemistry, the diagnosis of synovial sarcoma was suspected and was confirmed by FISH analysis. The patient was treated with right upper bilobectomy. Due to R1-resection status, postsurgical systemic chemotherapy was administered. Primary pulmonary synovial sarcoma is a rare primary lung tumor. Due to extensive size of the tumor with pleural and mediastinal invasion only a R1-resection status could be achieved by thoracic surgery.

Specificity of TLE1 Expression in Unclassified High-grade Sarcomas for the Diagnosis of Synovial Sarcoma

Expression of the transducin-like enhancer of split 1 (TLE1) by immunohistochemistry (IHC) has been widely used as a biomarker for the diagnosis of synovial sarcoma. Although TLE1 expression can be identified in more than 90% of synovial sarcomas, positive staining has been reported in up to one third of nonsynovial sarcomas, including peripheral nerve sheath tumors and neoplasms of fibrous and adipose tissues. The low specificity of this test in soft tissue tumors raises concern on its clinical application as a diagnostic biomarker. As synovial sarcoma is frequent among the differential diagnosis of unclassified high-grade sarcomas, and considering that the specificity of TLE1 antibody in this tumor group remains unclear, we evaluated TLE1 expression by IHC in 42 unclassified high-grade sarcomas. SS18 (SYT) gene break-apart analyses by fluorescence in situ hybridization were simultaneously performed as a gold standard biomarker for synovial sarcoma. Five cases that were positive for the SS18 break-apart by fluorescence in situ hybridization were also positive for TLE1 by IHC, whereas the remaining 37 cases negative for SS18 break-apart were all negative for TLE1. The results showed no evidence of nonspecific TLE1 expression in the nonsynovial high-grade sarcomas. We concluded that TLE1 is a highly specific biomarker for synovial sarcoma in the setting of differential diagnosis of unclassified high-grade sarcomas.

Primary synovial sarcoma of the stomach—A case report and review of the literature

Synovial sarcoma (SS) is a mesenchymal spindle cell tumor which displays variable epithelial differentiation. It commonly arises around the major joints or tendon sheaths in young adults, but is not commonly seen in the stomach. We experienced a case of primary gastric SS. The patient is a 22-year-old male, who presented with epigastric pain. Upper endoscopy showed an ulcer of 25mm in diameter with marginal elevation on the posterior mid-gastric body. Biopsy of the ulcer base showed monotonous proliferation of small spindle-shaped cells on HE-stain. On immunohistochemical staining, these cells were positively stained with vimentin, cytokeratin, epithelial membrane antigen, and CD99, but were negative for KIT, CD34, desmin, and S-100 protein. These findings were compatible with SS of monophasic type. Diagnosis of primary gastric SS was made because there were no other primary lesions, nor metastatic lesions. The wedge resection was performed. Reverse transcriptase polymerase chain reaction (RT-PCR), using the RNA from frozen neoplastic tissue of the resected specimen, detected a fusion gene called SYT-SSX1, specific for SS. Though SS arising in the stomach is rare, it should be considered in the differential diagnosis of KIT-negative gastric spindle cell tumor.

Synovial Sarcoma of the Larynx Treated by Supraglottic Laryngectomy: Case Report and Literature Review

We describe a case of synovial sarcoma of the larynx, and we discuss the use of fluorescence in situ hybridization (FISH) in confirming the diagnosis. The patient was a 21-year-old woman who presented with a recurrence of a previously resected supraglottic tumor of the aryepiglottic folds. A horizontal supraglottic laryngectomy was performed, and the 0.5-cm tumor was resected. Histopathologic study suggested that it was a biphasic malignant tumor compatible with a synovial sarcoma. The diagnosis of synovial sarcoma was confirmed by FISH immunohistochemistry with the use of an SYT break-apart probe. The patient recovered satisfactorily, but at follow-up 5 years and 4 months later, tumoral activity was evident in the left side of the neck. A biopsy found that 5 lymph nodes contained a metastasis of the synovial sarcoma. Again, a bilateral neck dissection was performed, and it revealed that 16 of 16 right-side nodes and 36 of 36 left-side nodes were negative. Two months later, the patient received 46 Gy of radiotherapy in 23 sessions. She remained free of disease during 2 more years of follow-up. Synovial sarcoma of the larynx is a rare entity. Organ preservation seems to be indicated in these cases. The histologic diagnosis may be difficult. In this case, the identification of a genetic mutation corroborated the diagnosis.

Primary gastric synovial sarcoma: molecular diagnosis and prediction of prognosis

A 42-year-old Japanese woman complained of upper abdominal pain. Endoscopic examination demonstrated an elevated lesion in the body of the stomach, and a biopsy specimen demonstrated proliferation of atypical spindle cells. She underwent partial gastrectomy; the resected tumor measured 3.5 × 2.8 × 1.2 cm in size. Histological examination disclosed the haphazard proliferation of spindle cells in the mucosa mixed with less prominent epithelioglandular component. The spindle cells were positive for cytokeratin, vimentin, EMA and CD99, but not for KIT, DOG1, desmin or S100. Reverse transcription-polymerase chain reaction using paraffin sections amplified a SYT-SSX1 chimera transcript. A diagnosis of synovial sarcoma was made. There has been no sign of recurrence or metastasis for 6 years after the operation. Synovial sarcoma in the stomach is very rare. Since differential diagnosis of synovial sarcoma from carcinosarcoma and mesenchymal tumors is critical for the treatment and prediction of prognosis, accurate diagnosis with molecular analysis is essential.

Synovial sarcoma presenting with huge mediastinal mass: a case report and review of literature

BackgroundSynovial sarcoma presenting in the mediastinum is exceedingly rare. Furthermore, data addressing optimal therapy is limited. Herein we present a case where an attempt to downsize the tumor to a resectable state with chemotherapy was employed.Case presentationA 32 year female presented with massive pericardial effusion and unresectable huge mediastinal mass. Computed axial tomography scan - guided biopsy with adjunctive immunostains and molecular studies confirmed a diagnosis of synovial sarcoma. Following three cycles of combination Ifosfamide and doxorubicin chemotherapy, no response was demonstrated. The patient refused further therapy and had progression of her disease 4 months following the last cycle.ConclusionSynovial sarcoma presenting with unresectable mediastinal mass carry a poor prognosis. Up to the best of our knowledge there are only four previous reports where primary chemotherapy was employed, unfortunately; none of these cases had subsequent complete surgical resection. Identification of the best treatment strategy for patients with unresectable disease is warranted. Our case can be of benefit to medical oncologists and thoracic surgeons who might be faced with this unique and exceedingly rare clinical scenario.

Multimodality management of synovial sarcoma: Review of single institutional experience.

e21506 Background: Soft tissue sarcomas (STS) are rare malignancies constituting 1% of all solid tumors. Synovial sarcoma (SS) constitutes 5-10% of all sarcomas. Histopathologically SS is classified as Monophasic, Biphasic and Poorly differentiated varieties and majority are high grade. There is paucity of literature pertaining to SS from developing countries. Methods: Study population was selected from a prospectively maintained STS database at the department of Surgical Oncology, Dr BRAIRCH, AIIMS. All patients with pathological diagnosis of SS were included for the analysis. Results: A total of 446 patients of STS were treated from 1995 to 2009 and 80 cases of pathologically proven SS were selected. Median age at diagnosis was 33 years. There were 53 males (66.3%) and 27 females (33.8%). Most common site was proximal lower limb, majority involving thigh. Sixty one patients presented with prior inadequate interventions including intralesional excision or marginal excision. Sixty seven cases had tumors more than 5 cm in size and 27 more than 10 cm. Lymph nodes were seen in 9 patients (11.3%) but only 4 showed pathological involvement. According to MSKCC staging 83% had stage III disease and stage I and II constituted 10.5%. Ten patients had metastasis at presentation and all of them had lung metastasis. Among the extremity sarcoma, 35 (43.8%) patients had limb salvage surgery and the rest required amputations due to advanced nature of disease. Overall 15% of cases required reconstruction and only 6 had positive margin. Postoperatively 35 patients received radiotherapy and 52 received chemotherapy (Adriamycin Ifosamide based). At a median follow up of 59 months,10 patients had local recurrence and 34 (42.5%) patients had systemic relapse mainly in the lungs (27 patients). At last follow up, 58 patients were alive of which 44 were disease free. The overall 5 year survival was 52%. Conclusions: SS is a rare tumor involving younger age group. Due to lack of awareness among patients and physician, majority present with suboptimal surgical intervention or advanced stage in developing countries resulting in a low limb salvage rate. Most common site of relapse is lung despite multimodality management resulting in a modest 5-year survival of 52%.

Rapidly progressive course of primary renal synovial sarcoma: Case report

Primary kidney sarcoma, especially synovial sarcoma (SS), is a very rare neoplasm. Preoperative signs and symptoms are very similar to renal cell carcinoma, therefore, the proper diagnosis is very difficult and usually made after nephrectomy.This is a case report of primary renal SS. A 38-year-old man presented with a history of fever and hematuria, and right flank pain 3 weeks ago. Abdominal computerized tomography revealed a heterogeneous well-marginated soft tissue mass arising in the lower part of the right kidney. Right nephrectomy was performed. A cystic tumor of 120 x 85 mm in size with soft solid growth, and with the extensive areas of hemorrhage and necrosis was seen on gross examination. Histopathology revealed a neoplasm composed of solid monomorphic sheets of spindle cells. Immunohistochemistry showed tumor cells strongly positive for BCL2, CD99, CD56 and vimentin, and focally positive for epithelial membrane antigen (EMA). The histological diagnosis of primary renal SS was based on morphology and immunohistochemistry. FISH analysis and RT-PCR was carried out on formalin-fixed paraffin-embedded tissue sections. The molecular analysis demonstrated translocation of SYT gene on chromosome 18 and SSX2 gene on chromosome X. The findings were consistent with diagnosis of SS. Our case shows that histopathological diagnosis of primary kidney SS, although difficult, is possible to be made on the basis of morphological and immunohistochemical analysis. However, this diagnosis should be corroborated by molecular techniques confirming SYT-SSX translocation on chromosome 18 and chromosome X. Here we present visceral monophasic SS with aggressive clinical course and poor outcome.

A rare case of monophasic pleuropulmonary synovial sarcoma

Pleuropulmonary synovial sarcoma is a diagnostic challenge. Synovial sarcoma is a soft tissue tumor of joints and extremities and are rarely seen in the mediastinum. We report this tumor at a very unusual location – the mediastinum in a 40-year-old female. The histopathology picture along with the location suggested a differential diagnosis of solitary fibrous tumor or mesothelioma, but immunohistochemistry helped in reaching the diagnosis of synovial sarcoma.

A rare case of monophasic pleuropulmonary synovial sarcoma

Pleuropulmonary synovial sarcoma is a diagnostic challenge. Synovial sarcoma is a soft tissue tumor of joints and extremities and are rarely seen in the mediastinum. We report this tumor at a very unusual location – the mediastinum in a 40-year-old female. The histopathology picture along with the location suggested a differential diagnosis of solitary fibrous tumor or mesothelioma, but immunohistochemistry helped in reaching the diagnosis of synovial sarcoma.

Fine needle aspiration of primary mediastinal synovial sarcoma: Cytomorphologic, immunohistochemical, and molecular study

The cytologic diagnosis of synovial sarcoma (SS) can be difficult when it occurs in unusual locations, atypical age groups, and/or have unusual morphology. We report a case of primary mediastinal SS in a 65-year-old male with a long smoking history who presented with increasing shortness of breath and was found to have a 14.2 cm mediastinal mass. Smears from the endobronchial ultrasound guided fine needle aspiration of the mass were moderately cellular consisting of loosely cohesive clusters, some of which demonstrated nuclear molding, and dispersed single cells. The relatively uniform tumor cells had a high nuclear-to-cytoplasmic ratio, finely granular chromatin, and inconspicuous nucleoli. Some of the single cells had spindled morphology with unipolar wispy tails and naked nuclei. Based on the clinical presentation and the cytomorphologic features, our initial differential diagnoses included atypical carcinoid, small cell carcinoma, basaloid squamous cell carcinoma, sarcoma, and lymphoma. Immunohistochemical studies on the cell block sections revealed that the tumor cells were focally positive for cytokeratin and diffusely positive for CD56, while negative for CD45, synaptophysin and chromogranin. Ultimately, an immunohistochemical stain for TLE-1 demonstrated diffusely strong nuclear positivity and molecular studies showed the presence of the t(X; 18) SYT/SSX1 translocation confirming the diagnosis of SS. In this report, we describe the cytomorphologic features of SS, its diagnostic pitfalls, and potential mimics in the mediastinum.

Synovial sarcoma arising in the vulva cytogenetically confirmed by SYT break-apart rearrangement fluorescence in situ hybridization: A case report and discussion of diagnostic methods

Synovial sarcoma (SS) is a soft tissue sarcoma of unknown histogenesis that rarely occurs in the female genital tract. We report a case of SS occurring in the right vulva of a young Japanese female. The tumor was composed of poorly differentiated rounded cell areas, surrounded by fibroblastic spindle-shaped cell areas. Immunohistochemically, the tumor cells were focally positive for cytokeratin, vimentin, CD99, Bcl-2 and neuron-specific enolase. The tumor was suspected, but was difficult to confirm as it was an SS based solely on light-microscopic and immunohistochemical findings. Although reverse transcription polymerase chain reaction (RT-PCR) failed to detect SS-specific SYT-SSX fusion gene transcripts using an RNA sample extracted from the formalin-fixed paraffin-embedded tumor tissue, SYT break-apart rearrangement fluorescence in situ hybridization (SYT bar-FISH) successfully confirmed our diagnosis of SS for the tumor. Thus, SYT bar-FISH may be more suitable for the purpose of the molecular diagnosis of SS than conventional RT-PCR when using archival formalin-fixed paraffin-embedded tissue specimens.

GI Synovial Sarcomas

Synovial sarcoma accounts for about 10% of adult soft tissue sarcomas, with 80–90% located in the limbs. Gastrointestinal tract involvement is rare. Synovial sarcoma has a propensity for local recurrence and lung metastases, which can be delayed beyond 5 years. The t(X;18) translocation resulting in the expression of a SYT–SSX fusion protein is commonly seen. Demonstration of this type of genetic rearrangement by fluorescence in situ hybridization or PCR is fundamental to the diagnosis of synovial sarcoma in unusual sites. Owing to the rarity of this tumor in the gastrointestinal tract, the appropriate method and extent of surgical resection is uncertain.