Should molecular testing be required for diagnosing synovial sarcoma?

Synovial Sarcoma of the Submaxillary Salivary Gland: A Rare Location and Challenging Diagnosis

Synovial sarcoma is a high-grade sarcoma. The periarticular region, deep soft tissues, and the extremities are where it is most frequently found. The head and neck regions are rarely affected and salivary gland localization is rather rare, especially the submaxillary gland. The process of diagnosis and therapeutic management remains challenging, particularly in cases with uncommon tumor locations where the establishment of a universal therapeutic consensus is complicated. Early diagnosis and a multidisciplinary approach can lead to success without locoregional recurrence or distant metastases.

Massive low-grade myxoid liposarcoma of the floor of the mouth: A case report and review of literature

BACKGROUND

Oral liposarcoma is an extremely rare lesion that is often clinically misdiagnosed as a benign tumor due to its asymptomatic and indolent clinical course. Here, we report a case of massive low-grade myxoid liposarcoma (MLS) of the floor of the mouth.

CASE SUMMARY

A 71-year-old man presented with a huge mass in the left floor of the mouth. A biopsy was performed, and a diagnosis of a myxoid tumor suspicious for low-grade MLS or myxoma was made. Gadolinium-enhanced T1-weighted magnetic resonance imaging showed an intensely enhanced tumor lesion that occupies the left sublingual space and extends to the submandibular space. Submandibular dissection, tumor resection, and reconstruction with a radial forearm flap were performed. The surgical specimen exhibited histologically low-grade MLS. Fused in sarcoma (FUS, also known as TLS) and DNA damage-inducible transcript 3 (DDIT3, also known as CHOP) break-apart was not detected in the fluorescence in situ hybridization analysis. The tumor was completely encapsulated and did not require additional treatment. Furthermore, no recurrence was reported 40 mo after surgery.

CONCLUSION

We experienced an extremely rare, massive, low-grade MLS emerging from the floor of the mouth. Oftentimes, an MLS of the floor of the mouth lacks significant clinical findings and is often misdiagnosed. Although no FUS-DDIT3 fusion gene was detected, a low-grade MLS was ultimately diagnosed based on the histological findings.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of soft tissue tumors 2020 - Secondary publication

BACKGROUND

These clinical practice guidelines are intended to provide recommendations based on the best evidence obtained to date on key issues in clinical practice to improve the prognosis, diagnostic and therapeutic processes for patients with soft tissue tumors.

METHODS

The Guidelines Development Committee and Systematic Review Committee were composed of a multidisciplinary team of specialists who play an important role in soft tissue tumor care. Clinical questions (CQs) were determined by choosing key decision-making points based on Algorithms for the diagnosis and treatment of soft tissue tumors. The guidelines were developed according to the "Medical Information Network Distribution Service (Minds) Handbook for Clinical Practice Guideline Development 2014" and "Minds Manual for Clinical Practice Guideline Development 2017." Recommendation strength was rated on two levels and the strength of evidence was rated on four levels. The recommendations were decided based on agreement by 70% or more voters.

RESULTS

Twenty-two CQs were chosen by the Guidelines Development Committee. The Systematic Review Committee reviewed the evidence concerning each CQ, a clinical value judgment was added by experts, and the text of each recommendation was determined.

CONCLUSION

We established 22 CQs and recommendations for key decision-making points in the diagnosis and treatment of soft tissue tumors according to the Minds Clinical Practice Guideline development methods. We hope that these guidelines will assist the decision-making of all medical staff engaged in the treatment and diagnosis of soft tissue tumors, and eventually lead to improved soft tissue tumor care in the country.

Primary Intraosseous Synovial Sarcoma in the Mandible

Synovial sarcoma (SS) is a rare malignant mesenchymal tumor that mainly occurs in body extremities, being uncommon in the head and neck region. In the present study, we described a case of primary intraosseous SS arising in the mandible of a 22-year-old young male. The patient reported a painful swelling on the left side of the mandible for the last 7 months. Imaging exams showed the presence of an expansive and multilocular radiolucent lesion, extending from the left condyle to the mandibular body. The clinic diagnostic hypotheses were ameloblastoma or malignant neoplasm. Histologically, the lesion was characterized by a proliferation of spindle cells exhibiting vesicular nuclei and evident nucleolus. Neoplastic cells were positive for AE1/AE3, cytokeratin 7, vimentin, CD-99, and TLE-1 and negative for CD-34, S-100, SMA, and HHF-35. A combination of clinical, histologic, and immunohistochemical characteristics supported the diagnosis of SS. The patient was referred for treatment, and preoperative exams did not reveal any other tumor foci in the body of the patient. The final diagnosis was of a primary intraosseous SS of the mandible.

Primary synovial sarcoma of thyroid gland: A case report and review of literature

INTRODUCTION AND IMPORTANCE

Synovial cell sarcoma (SS) is an extremely rare mesenchymal malignancy, representing nearly 10% of all soft-tissue sarcomas. These high-grade soft tissue sarcomas commonly arise in the para-articular regions of lower extremities. However, 15% of Synovial sarcomas has been described at Unusual locations, including head, neck, and trunk. Herein, we describe the twelfth case of primary synovial cell sarcoma of thyroid with a literature review.

CASE PRESENTATION

A 43-year-old woman presented with complaint of a progressive neck mass for the last five-months. She developed with dysphagia and dyspnea nearly 2 months prior, without signs of hoarseness, and weight loss. Ultrasonography in which revealed a heterogeneous, hypervascularized thyroid mass. After total thyroidectomy immunohistochemistry was in favor of primary synovial cell sarcoma of thyroid. The diagnosis was confirmed via Molecular genetic analysis of the SYT-SSX fusion gene transcript using the RT- polymerase chain reaction method. Clinical Discussion: Primary thyroid SVS is an extremely rare malignancy with poor biological behavior. SVS has been known for its tendency to local and distal re-occurrence after a few years of treatment. SS can be classified into two subtypes of monophasic or biphasic based on the presence of mesenchymal and/or epithelial components. Accordingly, the most accurate diagnostic tool for SS is considered to be molecular genetic analysis for SYT/SSX fusion transcript.

CONCLUSION

Herein, we reported an extremely rare case of SVS of thyroid gland. These high-grade soft tissue sarcomas mainly present with an asymptomatic rapid growing neck mass. Unspecific clinical presentations and extreme rarity of this disorder, make the diagnosis of thyroid SVS very challenging. Due to paucity of data, there is not enough evidence to establish a reliable mortality rate. However, the prognosis of thyroid SVS seems unfavorable.

Mesenchymal tumours of the gastrointestinal tract

Mesenchymal tumours represent a heterogenous group of neoplasms encopassing benign, intermediate malignancy, and malignant entities. Sarcomas account for approximately 1% of human malignancies. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Traditionally, mesenchymal tumours are regarded as lesions the occurrence of which is mostly limited to somatic soft tissues. However, the occurrence of soft tissue tumours at visceral sites represent a well recognized event, and the GI-tract ranks among the most frequently involved visceral location. There exist entities such as gastrointestinal stromal tumours (GIST) and malignant gastointestinal neuroectodermal tumors that exhibit exquisite tropism for the GI-tract. This review will focus also on other relevant clinico-pathologic entities in which occurrence at visceral location is not at all negligible.

Synovial sarcoma with overwhelming glandular (adenocarcinoma-like) component: A case report and review of the literature

Synovial sarcoma is an uncommon tumor of soft tissue, characterized by a specific SS18-SSX1/2/4 fusion gene. It is generally a lesion composed of monomorphic spindle cells, and can sometimes show variable epithelial differentiation. Here, we present the case of a young woman with a synovial sarcoma of the abdominal wall that showed an overwhelming (>90 %) epithelial glandular component mimicking adenocarcinoma, and only rare spindled areas. The diagnosis was confirmed by detection of targeted fusion transcripts associated with synovial sarcoma. We review the literature pertaining to synovial sarcoma, and we show that this case is only the sixth molecularly proven epithelial predominant synovial sarcoma in the literature. This report emphasizes the importance of molecular approaches in modern soft tissue pathology. Recognition of synovial sarcoma with predominant glandular component is imperative in order to avoid misdiagnosis of the tumor as metastatic adenocarcinoma, another type of sarcoma with epithelial differentiation, or a carcinoma with a sarcomatous component (sarcomatoid carcinoma), all of which have markedly different clinical management.

Malignant Epithelioid Soft Tissue Tumours- A Pathologist's Perspective With Review of Literature

Background Soft tissue tumours with epithelioid morphology have many differential diagnoses, which include epithelioid sarcoma, malignant extrarenal rhabdoid tumour, epithelioid malignant peripheral nerve sheath tumour, epithelioid leiomyosarcoma, epithelioid angiosarcoma and sclerosing epithelioid fibrosarcoma. There are other rare entities also. They often express characteristic patterns of immunohistochemical markers that can be used to identify these tumours. Materials and methods This retrospective study comprises 22 cases of malignant soft tissue tumours with epithelioid differentiation diagnosed over a period of four years. Findings regarding clinical presentation, cytological findings, histopathological findings and immunohistochemical profile of the tumours were noted and analyzed. Results A total of 22 cases were included in the study including five cases of epithelioid sarcoma (conventional and proximal), three cases of epithelioid angiosarcoma and epithelioid myxofibrosarcoma, two cases of epithelioid malignant peripheral nerve sheath tumour, epithelioid gastrointestinal stromal tumour and clear cell sarcoma each, one case of epithelioid leiomyosarcoma, sclerosing epithelioid fibrosarcoma, malignant extrarenal rhabdoid tumour, monophasic synovial sarcoma and malignant and malignant perivascular epithelioid cell tumour each. Conclusion Pathologists should be aware of the various differential diagnoses of soft tissue tumours with epithelioid morphology. Over and above the clinical findings and morphological features, ancillary methods like immunohistochemistry help to arrive at a definitive diagnosis in most cases.

Primary synovial sarcoma of the lung: a rare presentation, diagnostic dilemma and review of literature

Primary synovial sarcoma of the lung (PSSL) is a rare tumour with only 0.5% incidence among other primary malignant lung tumours. Published medical literature regarding the natural history treatment protocol and clinical outcomes of PSSL remains limited. Here, we present a case of a 39-year-old man with primary synovial sarcoma with long-term follow-up, which was initially viewed as a metastasis from another unknown site. After evaluating histopathologically from the specimen post left lung metastasectomy and ruling out any other site for neoplastic changes, the diagnosis of PSSL was confirmed. Furthermore, this article reviews the literature and discusses various aspects of PSSL, including clinical presentation, radiological imaging and pathological characteristics, diagnostic dilemma, management and prognosis. This paper serves to provide an update and aims to enhance the understanding of PSSL. Timely diagnosis and treatment are imperative to achieve improved outcomes.

Immunohistochemical Analysis of CD99 and PAX8 in a Series of 15 Molecularly Confirmed Cases of Ewing Sarcoma

Ewing sarcomas are an uncommon group of malignant neoplasms. A multidisciplinary approach is highly recommended to reach a correct diagnosis, considering the clinical, radiological, and histopathological aspects. Since in up to 90% of cases, the translocation t (11; 22) (q24; q12) occurs resulting in a chimeric fusion transcript EWSR1-FLI-1. The pathologist has several tools in addition to conventional techniques (hematoxylin and eosin), such as immunohistochemistry, which plays a very important role in the differential diagnosis. We present a series of 15 cases of molecularly confirmed ES, in which we found a sensitivity of 100% for CD99 and 80% for PAX8 by immunohistochemistry. This indicates a high sensitivity; however, it is known that both CD99 and PAX8 are also expressed in other tumours. Therefore, molecular confirmation should be performed in all cases.

Laryngeal Synovial Sarcoma: A Systematic Review of the Last 40 Years of Reported Cases

Primary laryngeal synovial sarcoma is an extremely rare tumor predominantly affecting young adults. There are currently no well-defined guidelines to direct investigation and management, and treatment is largely based on what is known for synovial sarcoma of the upper and lower limbs. This PROSPERO-registered study aims to review the diagnostic methods, treatment regimens, and survival outcomes for patients with synovial sarcoma of the larynx. A systematic search of databases Medline, Embase, SCOPUS, and Web of Science was undertaken in December 2017. The literature search identified 1031 potentially relevant studies, and after the deletion of duplicates and excluded papers, 98 full-text articles were screened. A total of 39 cases were reviewed from 32 studies in the data extraction. The average age at the time of laryngeal synovial sarcoma diagnosis was 32 years (range, 11-79 years). In all cases (n = 39), patients underwent wide surgical excision, with 20 patients requiring a partial or total laryngectomy. A total of 18 patients received adjuvant and 3 received neoadjuvant radiotherapy. Chemotherapy was used in 10 cases, with ifosfamide the most frequently used agent. There was considerable variability in the order and combinations of the abovementioned treatments. No clinicopathologic factors or treatment regimens were associated with improved overall survival or lower rate of recurrence. There is a paucity of literature and heterogeneity in clinical approaches to this highly aggressive sarcoma. Reporting of cases must be standardized and formal guidelines must be established to guide clinical management.

Monophasic Synovial Sarcoma of Tongue: A Rarest of Rare Case Scenario

Synovial sarcoma is a rare tumour of head and neck. Primary synovial sarcoma of tongue is very uncommon. Based on morphology, it can be classified as classical biphasic variant, monophasic spindle cell variant, monophasic epithelial variant and poorly differentiated variant. The authors with an index case of 74 year old lady with monophasic spindle cell synovial sarcoma of oral tongue which is one of the rarest variants (our case is the 15th case reported of synovial sarcoma of the tongue and only the 3rd case in the world which had a monophasic histopathologic pattern) studied the morphology and described the disease entity in detail. She was treated with wide local excision of sarcoma followed by adjuvant radiotherapy.

SMARCB1-deficient Tumors of Childhood: A Practical Guide

The SMARCB1 gene ( INI1, BAF47) is a member of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex, involved in the epigenetic regulation of gene transcription. SMARCB1 acts as a tumor suppressor gene, and loss of function of both alleles gives rise to SMARCB1-deficient tumors. The prototypical SMARCB1-deficient tumor is the malignant rhabdoid tumor (MRT) which was first described in the kidney but also occurs in soft tissue, viscera, and the brain (where it is referred to as atypical teratoid rhabdoid tumor or AT/RT). These are overwhelmingly tumors of the very young, and most follow an aggressive and ultimately lethal course. Morphologically, most but not all contain a population of "rhabdoid" cells, which are large cells with abundant cytoplasm, perinuclear spherical inclusions, and eccentric vesicular nuclei with large inclusion-like nucleoli. MRT immunohistochemistry reveals complete loss of SMARCB1 nuclear expression, and molecular analysis confirms biallelic SMARCB1 inactivation in the vast majority. Rare AT/RTs have loss of SMARCA4, another SWI/SNF member, rather than SMARCB1. With the widespread adoption of SMARCB1 immunohistochemistry, an increasing number of SMARCB1-deficient tumors outside of the MRT-AT/RT spectrum have been described. In addition to MRT and AT/RT, pediatric tumors with complete loss of SMARCB1 expression include cribriform neuroepithelial tumor, renal medullary carcinoma, and epithelioid sarcoma. Tumors with variable loss of SMARCB1 expression include subsets of epithelioid malignant peripheral nerve sheath tumor, schwannomas arising in schwannomatosis, subsets of chordomas, myoepithelial carcinomas, and sinonasal carcinomas. Variable and reduced expression of SMARCB1 is characteristic of synovial sarcoma. In this review, the historical background, clinical characteristics, morphology, immunohistochemical features, and molecular genetics most germane to these tumors are summarized. In addition, familial occurrence of these tumors (the rhabdoid tumor predisposition syndrome) is discussed. It is hoped that this review may provide practical guidance to pathologists encountering tumors that have altered expression of SMARCB1.

A primary gastric synovial sarcoma: A case report and literature review

RATIONALE

When a gastric spindle cell tumor is observed, the possibility of synovial carcinoma, besides common mesenchymal tumor, should also be considered.

PRESENTING CONCERNS OF THE PATIENT

The patient is a 51-year-old American woman who underwent medical check-up at a general hospital. Upper endoscopy showed a 2-cm sized mass covered with intact mucosa, and a central depression located on the posterior wall of the mid body. Biopsy of the mass showed focal atypical cells proliferation in mucosa on hematoxylin & eosin (H&E) staining. Endoscopic ultrasound showed a 17-mm homogenously hypoechoic mass within the submucosal layer.

INTERVENTIONS

After diagnostic endoscopic submucosal dissection was performed, H&E and immunohistochemical staining showed synovial sarcoma (SS). To confirm the diagnosis, reverse transcriptase-polymerase chain reaction was performed, revealing a chimeric transcript of the SYT-SSX1 fusion gene. The diagnosis of primary gastric SS was confirmed because no evidence of possible primary lesions or metastatic lesions was observed. Therefore, the patient underwent distal gastrectomy.

OUTCOMES

After surgery, the surgical specimen demonstrated no residual tumor cells. The patient received no adjuvant therapy, and there has been no evidence of local recurrence or distant metastasis for 2 months after the operation.

LESSONS

When gastric subepithelial tumor is suspicious, we should also consider gastric SS.

Factors Associated With Survival in Patients With Synovial Cell Sarcoma of the Head and Neck: An Analysis of 167 Cases Using the SEER (Surveillance, Epidemiology, and End Results) Database

IMPORTANCE

Synovial cell sarcoma of the head and neck (SCSHN) is a rare tumor associated with significant morbidity and mortality. The literature regarding these tumors is limited to case series and case reports. We used data from the population-based US Surveillance, Epidemiology, and End Results (SEER) cancer registry to determine factors affecting both overall survival and disease-specific survival of patients with SCSHN.

OBJECTIVE

To determine the clinicopathologic and therapeutic factors determining survival in patients with SCSHN.

DESIGN, SETTING, AND PARTICIPANTS

The SEER registry was reviewed for patients with primary SCSHN from January 1, 1973, to January 1, 2011.

MAIN OUTCOMES AND MEASURES

Overall survival (OS) and disease-specific survival.

RESULTS

A total of 167 cases of SCSHN were identified. The mean (SD) age at diagnosis was 37.9 (17.3) years, and 100 (59.9%) of the patients were males. The monophasic spindle cell and biphasic variants were the most common histologic subtypes. Surgical resection and radiotherapy were performed in 150 (89.8%) and 108 (64.7%) of the cases, respectively. The median OS at 2, 5, and 10 years was 77%, 66%, and 53%, respectively. Univariate Kaplan-Meier survival analysis revealed that age, race, and tumor stage and size were associated with improved survival. Histologic subtype was not associated with significant differences in survival. Radiotherapy was associated with improved disease-specific survival (hazard ratio [HR], 0.29 [95% CI, 0.12-0.68]; P = .003), but surgical management was not associated with improved survival (HR, 0.52 [95% CI, 0.19-1.46]; P = .21). Multivariate Cox regression analysis revealed that size greater than 5 cm (adjusted HR, 3.60 [95% CI, 1.43-9.08]; P = .007) and stage at presentation (adjusted HR, 3.86 [95% CI, 2.01-7.44]; P < .001) were independent determinants of OS. In separate analysis of cohorts with tumors 5 cm or less and larger than 5 cm, stage at presentation was found to be a significant indicator of the probability of survival in both cohorts (adjusted HR, 3.10 [95% CI, 1.46-6.60]; P = .003 and 5.32 [95% CI, 1.49-18.98]; P = .01, respectively); surgical resection and radiotherapy were not associated with differential survival outcomes using this model.

CONCLUSIONS AND RELEVANCE

Synovial cell sarcoma of the head and neck is rare. Independent significant determinants of survival include size (>5 cm) and stage at presentation. Histologic subtype of the tumor is not a significant indicator of the probability of survival. Surgical resection and radiotherapy were not independent determinants of survival.

Transducer-like Enhancer of Split 1 as a Novel Immuno- histochemical Marker for Diagnosis of Synovial Sarcoma

BACKGROUND

Synovial sarcoma is a mesenchymal neoplasm that accounts for around 10% of all soft tissue sarcomas. The diagnosis of synovial sarcoma can be a challenging task, particularly with small biopsy specimens.

AIM

We investigated transducer-like enhancer of split 1 (TLE1), monoclonal antibody, expression by immunohistochemical analysis in a group of 74 synovial sarcoma cases, 20 cases of MPNST, 12 cases of neurofibroma, 15 cases of schwannoma, 5 cases of MFH, 10 cases of lieomyosarcoma and 10 cases of solitary fibrous tumor.

MATERIALS AND METHODS

Whole tissue sections were examined: (39 biphasic and 35 monophasic). Nuclear immunoreactivity was scored as negative (<5% of cells positive), 1+(mild /5-25%), 2+ (moderate/25-50%), and 3+ (strong >50%).

RESULTS

Overall, 71 (96%) of 74 synovial sarcomas were positive for TLE1, including 37 biphasic (95%) and 34 monophasic (97%) tumors. Other spindle cell tumors showed very low or absent staining of TLE1.

CONCLUSIONS

We conclude that TLE1 is a sensitive marker and can be a useful diagnostic marker for synovial sarcoma, particularly the monophasic forms.

Primary pleuropulmonary and mediastinal synovial sarcoma: a clinicopathologic and molecular study of 26 genetically confirmed cases in the largest institution of southwest China

BACKGROUND

Primary pleuropulmonary and mediastinal synovial sarcomas (PPMSSs) are extremely rare. The authors present the largest series in an Asian population.

METHODS

Between 2000 and 2015, 26 genetically confirmed PPMSSs were included. The clinicopathologic features of all of the cases were reviewed. Immunohistochemical staining was carried out using the following antibodies: TLE1, cytokeratin (AE1/AE3), EMA, CD99, Bcl-2, CK7, CD34, S-100 protein, and Ki-67. The chromosomal translocation t(X;18)(p11.2;q11.2) was detected by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). We compared the clinical, pathologic, immunohistochemical, and molecular features of this series with that of the previous series and soft tissue synovial sarcomas.

RESULTS

This series included 17 males and nine females. The median age was 36.5 years (range, 16-72 years). The tumors involved the lung (76.9 %), pleura (15.4 %), and mediastinum (7.7 %). The median tumor size was 6 cm (range 2.3 ~ 24 cm). The majority of the tumors were well-circumscribed. The tumors were classified as monophasic (84.6 %), biphasic (3.8 %), and poorly differentiated (11.5 %) types. The tumors were graded as French Federation of Cancer Centers (FNCLCC) grade 2 (62.5 %) and FNCLCC 3 (37.5 %). Diffuse immunostaining for TLE1, BCL-2, and CD99 was identified in 91.7, 95.7, and 56.0 % of the tumors, respectively. Focal positivity was seen with EMA (84.6 %), CK7 (55.6 %), cytokeratin (AE1/AE3) (68.0 %), CD34 (5.0 %), and S-100 protein (21.7 %). A high Ki-67 index (≥10 %) was observed in 91.3 % of the tumors. The fusion transcripts included SS18-SSX1 (15/22, 68.2 %), SS18-SSX2 including variants (6/22, 27.3 %), and SS18-SSX4 (1/22, 4.5 %) fusions. The remaining four cases showed positivity for SS18 rearrangement by FISH. Surgical excision of tumors or lobectomy were performed in 20 patients, and seven of the patients underwent adjuvant therapy. Clinical follow-up was available in 73.1 % cases, with a median follow-up of 12.0 months. The median survival time was 14.5 months. Tumor resection (p = 0.024) and no residual tumor (p = 0.004) were associated with an improved overall survival time.

CONCLUSIONS

PPMSS is a highly aggressive neoplasm. Extensive surgical resection of the tumor and more effective adjuvant therapy should be advocated. PPMSS must be differentiated from similar diseases.

Synovial sarcoma of kidney in a child: A rare presentation

There are no reported cases in the literature of primary renal synovial sarcoma in pediatric patients. The management of renal synovial sarcoma has been extrapolated from the management of soft tissue sarcomas at other sites. We present a 4-year-old female who was suspected to have Wilms’ tumor. The patient underwent guided biopsy as she did not respond to neoadjuvant chemotherapy for Wilms’ tumor. The biopsy was consistent with primary renal synovial sarcoma. The child was treated with change in her neoadjuvant chemotherapy regimen and surgery. The diagnosis of synovial sarcoma was confirmed by demonstrating the t (X, 18) translocation using polymerase chain reaction.

Clinical effect of molecular methods in sarcoma diagnosis (GENSARC): a prospective, multicentre, observational study

BACKGROUND

Advances in molecular genetics of sarcoma have enabled the identification of type-specific aberrations. We aimed to assess the clinical effect of systematic implementation of molecular assays to improve sarcoma misdiagnosis.

METHODS

In this multicentre, observational study, we recruited patients from 32 centres of the French Sarcoma Group/Reference Network in Pathology of Sarcomas. Eligibility criteria included: biopsy or surgical resection; suspicion of: dermatofibrosarcoma protuberans (cohort 1), dedifferentiated liposarcoma (cohort 2), Ewing's sarcoma family of tumours (cohort 3), synovial sarcoma (cohort 4), alveolar rhabdomyosarcoma (cohort 5), and myxoid or round cell liposarcoma (cohort 6); review by one sarcoma-expert pathologist; availability of frozen material (except for cohort 1 of patients with dermatofibrosarcoma protuberans because anti-CD34 immunohistochemistry is performed on paraffin-embedded tissue); and patient information. For each case, the pathologist made one primary diagnosis followed by up to two differential diagnoses, based on histological characteristics only. Each diagnosis was classified as certain, probable, or possible. For each case to determine the molecular classification, we did fluorescence in-situ hybridisation on paraffin-embedded samples. We also did comparative genomic hybridisation and quantitative PCR (cohort 2) or reverse transcriptase PCR (cohorts 3-6) on frozen and paraffin-embedded samples. We made a final diagnosis based on the molecular results. The clinical effect of diagnosis correction was assessed by a board of experts.

FINDING

Between June 22, 2009, and Oct 30, 2012, 395 patients were enrolled in the study, of which 384 were eligible for inclusion. The diagnosis was eventually modified by molecular genetics for 53 patients: eight (16%) of 50 patients with dermatofibrosarcoma (cohort 1), seven (23%) of 30 patients with dedifferentiated liposarcoma (cohort 2), 13 (12%) of 112 with Ewing's sarcoma family of tumours (cohort 3), 16 (16%) of 97 patients with synovial sarcoma (cohort 4), seven (15%) of 46 patients with alveolar rhabdomyosarcoma (cohort 5), and two (4%) of 49 patients with myxoid or round cell liposarcoma (cohort 6), with an effect on primary management or prognosis assessment in 45 cases.

INTERPRETATION

Molecular genetic testing should be mandatory for diagnostic accuracy of sarcoma and appropriate clinical management, even when histological diagnosis is made by pathologist experts in this field.

FUNDING

French National Cancer Institute and Nice University Hospital.

Primary Synovial Sarcoma (SS) of the digestive system: a molecular and clinicopathological study of fifteen cases

BACKGROUND

Recently a few cases of synovial sarcoma (SS) of the abdominal viscera have been reported, raising awareness about the potential for confusion between this entity and KIT-negative gastrointestinal stromal tumors (GIST). We report the clinicopathological, immunophenotypical and molecular features of fifteen more SS occurring in the stomach (8 cases), epigastric region (one case), small intestine (one case), large intestine (three cases), involving both the terminal ileum and the caecum (one case) and liver (one case).

METHODS

Immunostains for SMA, DESMIN, CD34, CD117, S100, EMA, CK AE1/3, TLE1, CD56, CD99, BCL2, DOG1 were performed. Rearrangement of SS18 gene region was screened in all cases: by conventional karyotype in one case, the remaining cases were screened either by interphase FISH or Q-PCR or both.

RESULTS

Ten patients were male and five female, with an age range of 17-61 years (median 44). Tumor size ranged from 2 to 15 cm (median 8). Mitoses per 10 HPF ranged from 4 to 27 (median 9.5). Eleven tumors were monophasic fibrous SS, one biphasic SS and three poorly differentiated SS. SMA, Desmin, CD34, CD117 and S100 were negative in all cases, whereas EMA and/or CK AE1/AE3 were positive in all cases. TLE1, BCL2 and CD56 were positive in all tested cases. DOG1 was positive in one case. SS18 gene region rearrangement was demonstrated in all cases. A fusion transcript was amplified in eight cases: either SS18-SSX2 or SS18-SSX1 respectively in four cases each.

CONCLUSIONS

SS is increasingly recognized at visceral sites. Molecular analyses play a key role when dealing with usual histotypes in unusual sites. Correct diagnosis is crucial for appropriate therapy.

Primary Pulmonary Synovial Sarcoma during Pregnancy: A Diagnostic and Therapeutic Dilemma

Synovial sarcoma is a rare soft tissue sarcoma that typically arises in the extremities of young adults. We report a case of a 26-year-old pregnant woman with biopsy-proven primary synovial sarcoma of the lung that was treated with chemotherapy with radiographic response. This is only the third documented case of primary pulmonary synovial sarcoma occurring during pregnancy and the first case where chemotherapy was given.

Exomic analysis of myxoid liposarcomas, synovial sarcomas, and osteosarcomas

Bone and soft tissue sarcomas are a group of histologically heterogeneous and relatively uncommon tumors. To explore their genetic origins, we sequenced the exomes of 13 osteosarcomas, eight myxoid liposarcomas (MLPS), and seven synovial sarcomas (SYN). These tumors had few genetic alterations (median of 10.8). Nevertheless, clear examples of driver gene mutations were observed, including canonical mutations in TP53, PIK3CA, SETD2, AKT1, and subclonal mutation in FBXW7. Of particular interest were mutations in H3F3A, encoding the variant histone H3.3. Mutations in this gene have only been previously observed in gliomas. Loss of heterozygosity of exomic regions was extensive in osteosarcomas but rare in SYN and MLPS. These results provide intriguing nucleotide-level information on these relatively uncommon neoplasms and highlight pathways that help explain their pathogenesis.

An unusual breast mass: primary synovial sarcoma

We describe a 54-year-old woman presenting with mastalgia and a 6 mm breast lesion on imaging. Core biopsy revealed a lesion characterised by a predominant epithelioid and a minor spindle cell component. Our differential diagnosis included intraduct papilloma/adenoma and adenomyoepithelioma. However, initial immunohistochemistry did not support these diagnoses and further immunohistochemistry raised the possibility of a synovial sarcoma. This was confirmed with the finding, using fluorescence in-situ hybridisation, of the characteristic translocation t(x; 18) (p11.2; q11.2). Establishing a diagnosis of synovial sarcoma at unusual sites may be difficult, especially when limited tissue is available, for example, within a core biopsy. In this case, immunohistochemistry was useful, but cytogenetics was the key additional investigation. It is important to consider the possibility of rare tumours when the morphological and immunohistochemical features of a lesion initially appear conflicting or inconclusive.

Primary monophasic synovial sarcoma of the tonsil: immunohistochemical and molecular study of a case and review of the literature

Synovial sarcoma (SS) arises primarily in the lower extremities with a predilection for sites in proximity to large joints, such as the knee. It rarely occurs in the head and neck region, and the tonsil is an unusual site for the tumor, with only eight previously published cases in this anatomical site. We present a case of a primary monophasic SS arising in the right tonsil in a 63-year-old male. His medical history was noncontributory. Immunohistochemistry showed that cytokeratin OSCAR, EMA, Bcl-2, vimentin, PGP 9.5, and TLE1 were diffusely positive. A molecular analysis using RT-PCR indicated that the patient was positive for the SYT/SSX1 fusion transcript. A diagnosis of monophasic synovial sarcoma of the tonsil was made.

Primary monophasic synovial sarcoma lung with brain metastasis diagnosed on transthoracic FNAC: Report of a case with literature review

Synovial sarcoma is highly malignant tumor of soft tissues, occurring chiefly in the extremities and limb girdle with a propensity for local recurrence and sometimes metastases to the lungs. Primary synovial sarcoma arising in the lungs is rare and brain metastasis as presentation is further uncommon. We report a case of primary monophasic synovial sarcoma lung presenting with brain metastasis in a 35-year-old male patient. The diagnosis was made on percutaneous transthoracic needle aspiration from left-sided pulmonary mass and later confirmed by immunohistochemistry. The utility of preoperative diagnosis by percutaneous aspiration cytology is also stressed.

Primary Monophasic Synovial Sarcoma Arising in the Mesentery: Case Report of an Extremely Rare Mesenteric Sarcoma Confirmed by Molecular Detection of a SYT-SSX2 Fusion Transcript

Synovial sarcoma arises in the para-articular tissues, and it can also occur in various unexpected sites. We report a rare case of primary monophasic synovial sarcoma (MSS) arising in the mesentery. A 59-year-old man presented with a palpable abdominal mass. On microscopic examination, the entire tumor comprised a dense proliferation of the spindle cells without epithelial components. The tumor cells were positive for transducin-like enhancer of split 1, bcl-2, epithelial membrane antigen and CD99 but negative for CD34, CD117, alpha-smooth muscle actin, cytokeratin, and calretinin on immunohistochemistry. The reverse transcriptase-polymerase chain reaction revealed a single 151-bp fragment representing the SYT-SSX2 fusion transcript. Because mesenteric MSS is extremely rare and many cases display histologic findings that overlap with those of more frequently involved tumors such as hemangiopericytoma and gastrointestinal stromal tumor, there is a chance of making an incorrect diagnosis that can result in an inappropriate treatment.

Soft tissue tumors of uncertain origin

Many soft tissue tumors of childhood lack obvious differentiation toward a defined mesenchymal tissue type or have a phenotype that does not correspond to any defined normal tissue. These challenging tumors are currently regarded as neoplasms of uncertain differentiation. Nonetheless, there have been great strides in the understanding of their pathologic and genetic features and biologic underpinnings. The application of new genetic information to the pathologic diagnosis among this group of tumors is an emerging area in diagnostic pediatric pathology. This article reviews the clinicopathologic features of tumors of uncertain and/or miscellaneous origin, with an emphasis on the unique aspects of these neoplasms in children and adolescents, use of diagnostic adjuncts, and differential diagnosis.

Primary synovial sarcoma involving the submandibular gland

Synovial sarcoma represents 5.6%-10% of all soft-tissue sarcomas. Adolescents and young adults are most frequently affected, mainly in the deep soft tissue of the extremities. Only 10% of synovial sarcomas affect the head and neck region; most of these are biphasic. We describe a case of an 18-year-old man who complained of a mass in the right submandibular region that had been present for approximately 12 months. On surgical removal, microscopic analysis showed a tumor formed by sheets of malignant spindle cells involving the submandibular gland. Immunohistochemistry displayed positivity for AE1/AE3, CK18/8, epithelial membrane antigen, CD99, CD56, and TLE-1. Based on these immunohistochemical and histopathologic features, a diagnosis of monophasic synovial sarcoma was rendered. The patient was treated with adjuvant radiotherapy and after 1 year was free of disease. To the best of our knowledge, this is the first reported case of synovial sarcoma involving the submandibular gland.

Synovial Sarcoma of the Tongue Confirmed by Molecular Detection of the SYT-SSX2 Fusion Gene Transcript

Involvement of the tongue by a synovial sarcoma (SS) is an extremely rare event; there have only been 13 cases previously reported. The authors present herein a case of monophasic SS arising in the tongue in a 32-year-old woman. The neoplasm expressed cytokeratins AE1-3, OSCAR, and EMA as well as Bcl-2 and TLE1. Molecular analysis indicated that the patient tested positive for the SYT/SS2 fusion transcript.

Of mice and men: opportunities to use genetically engineered mouse models of synovial sarcoma for preclinical cancer therapeutic evaluation

BACKGROUND

Synovial sarcoma is a soft tissue malignancy with a predilection for adolescents and young adults. Despite recent improvements in the understanding of its character and etiology, few therapeutic advances have been made. The mortality rate is high among the young population it affects. The low incidence of most subtypes of sarcoma, such as synovial sarcoma, makes disease-specific trials difficult to organize. The biological differences between sarcoma subtypes make inclusion of multiple types in general trials unsatisfactory as well.

METHODS

A review of the literature regarding targetable pathways in synovial sarcoma was undertaken. A strategy has been devised to utilize available technologies in order to prioritize drug trial planning.

RESULTS

Cell culture and xenograft research with synovial sarcoma cell lines have identified some critical pathways that may be targetable. Promising therapeutic strategies include newer cytotoxic chemotherapies, antiangiogenic agents, anti-IGF1R pathway agents, anti-Bcl-2/proapoptotic agents, and histone deacetylase complex inhibitors.

CONCLUSIONS

We propose to prioritize potential therapeutic strategies via preclinical testing of agents in a genetic mouse model of synovial sarcoma. Preclinical optimization of treatment regimens can guide the development of more focused patient trials.

Immunohistochemical staining for TLE1 distinguishes synovial sarcoma from histologic mimics

Transducer-like enhancer of split 1 (TLE1) is overexpressed in synovial sarcomas. We investigated TLE1 expression by immunohistochemical analysis in a well-characterized series of synovial sarcomas and other mesenchymal tumors most commonly considered in the differential diagnosis. Whole tissue sections of 212 tumors were evaluated: 73 synovial sarcomas (23 biphasic, 28 monophasic, 22 poorly differentiated), 47 malignant peripheral nerve sheath tumors (MPNSTs), 49 solitary fibrous tumors (SFTs), 20 fibrosarcomatous variants of dermatofibrosarcoma protuberans, and 23 Ewing sarcomas/primitive neuroectodermal tumors (PNETs). All monophasic and poorly differentiated SSs and Ewing sarcoma/PNETs were previously confirmed to harbor t(X;18) and EWSR1 gene rearrangements, respectively. In total, 60 (82%) of 73 synovial sarcomas were positive for TLE1, including 18 biphasic (78%), 22 monophasic (79%), and 20 poorly differentiated (91%) tumors. Of the other tumors, only 7 MPNSTs (15%) and 4 SFTs (8%) were positive for TLE1, most of which showed only weak staining. TLE1 is a sensitive and specific marker for synovial sarcoma and can be helpful to distinguish synovial sarcoma from histologic mimics, particularly if moderate or strong staining is observed. In this study, only a small subset of MPNSTs and SFTs showed limited staining for TLE1.

Synovial sarcoma of the thyroid gland

Primary synovial sarcoma of the thyroid is an extremely rare condition which has only been reported twice in the literature. We herein report a case of highly aggressive and rapidly lethal primary synovial sarcoma of the thyroid. A 72-year-old woman presented with extensive local invasion, rapid progression, and early distant metastasis secondary to primary thyroid synovial sarcoma. The tumor exhibited an atypical histologic and immunohistochemical staining pattern. Detection of SYT/SSX fusion transcript confirmed the diagnosis of synovial sarcoma. Due to the aggressive nature of primary synovial sarcoma of the thyroid gland, early diagnosis and comprehensive treatment including wide resection and postoperative chemoradiation is required.

Malignant inguinal monophasic synovial sarcoma: report of a case and review of the literature

Background

A synovial sarcoma (SS) is an aggressive soft tissue tumor that classically occurs in the extremities near, but rarely within large joints, in young adults. Variable symptoms and clinical manifestations may be encountered and a definite diagnosis should depend on pathological results. This poses certain difficulties in arriving at a prompt diagnosis and appropriate treatment.

Case presentation

We report the case of a 68-year-old woman patient who presented an inguinal mass with swelling and pain in the right lower limb. She underwent surgery, and later received systematic intravenous chemotherapy. The pathological studies, especially the specific chromosomal translocation of a t(X;18) (p11.2;q11.2), confirmed the diagnosis as a synovial sarcoma. To the best of our knowledge, this is the first report of a monophasic synovial sarcoma in the inguinal region.

Conclusion

Besides making the readership aware of the rarity of location and age of this present case, this report distinctly highlights the great value of a molecular analysis of an SYT associated genetic alteration in the diagnosis of synovial sarcoma occurring at rare sites especially when immunochemical results are equivocal.

Primary pulmonary biphasic synovial sarcoma confirmed by molecular detection of a SYT-SSX2 fusion gene: report of 1 case

We experienced a case of primary pulmonary biphasic synovial sarcoma, which was confirmed by immunohistochemistry and molecular testing of SYT-SSX2 fusion transcripts. The patient was a 61-year-old man who presented with a well-defined mass in the left upper lung field on chest radiography. Left upper lobectomy with lymph node dissection was performed. Histological and immunophenotypic features were consistent with biphasic synovial sarcoma. Reverse transcriptase polymerase chain reaction, performed using RNA extracted from frozen tumor samples for the detection of SYT-SSX fusion gene, amplified a single 331-bp fragment that was characteristic of the SYT-SSX2 fusion transcripts. We report a case of primary pulmonary biphasic synovial sarcoma, which was confirmed by SYT-SSX2 fusion transcripts, and present a brief review of the literature on Korean cases.

Primary synovial sarcoma of the lung with intra-cardiac extension

Synovial sarcomas are a distinct clinical entity occurring most often in the lower extremities. They account for 10-14% of all soft tissue sarcomas. Pulmonary synovial sarcomas are quite rare and account for less than 0.5% of all intra-thoracic neoplasms. We present the first reported case of primary pulmonary synovial sarcoma with intra cardiac extension in a 53-year-old male who presented with chronic cough. Imaging revealed a large right upper lobe mass extending through the superior pulmonary veins into the left atrium. The patient underwent a right total pneumonectomy with extraction of the left atrial mass and left atrial reconstruction. Pathology and immunohistochemistry was diagnostic of primary pulmonary synovial sarcoma positive for SYT-SSX1 gene fusion transcription.