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

Primary synovial sarcoma of lung - A report of two cases

Primary synovial sarcoma (SS) is an uncommon lung tumor. The thigh, knee, ankle, foot, and upper extremities are the most often reported locations of origin. Sarcomas of the lung barely make up 0.1-0.5% of cases. This report presents two cases of primary pulmonary SS. Typically, the tumor manifests at a younger age. When the diagnosis of primary pulmonary SS is confirmed by clinical, histological, and immunohistochemical examinations, molecular testing is not necessary. Instead, radiological and histopathological findings are necessary for the diagnosis of SS. Early surgical intervention is recommended. The initial course of treatment for advanced SS includes ifosfamide and doxorubicin.

Primary Intrathoracic Synovial Sarcoma: An Analysis of Outcomes of This Rare Disease

Background: Primary intrathoracic synovial sarcoma (SS) is a rare entity. The objective of this study was to evaluate survival outcomes for patients with intrathoracic SS presenting with localized disease at diagnosis. Methods: We conducted a retrospective review of 63 patients diagnosed with intrathoracic SS between 1997 and 2020. The Kaplan-Meier method and log-rank test were used to estimate the progression-free survival (PFS), overall survival (OS), local recurrence-free survival (LRFS), and metastasis-free survival (MFS). The hazard ratios were estimated by using Cox proportional hazards regression. Median follow-up time, age-at-diagnosis, and primary tumor size were 31 months (range: 4-218 months), 43 years (range: 18-77), and 7 cm (range: 1-23), respectively. Results: Sixty-two of sixty-three (98%) patients had their primary tumor resected, from whom eighteen (29%) and forty-three (69%) had received neo/adjuvant radiotherapy and chemotherapy, respectively. Median PFS, OS, and MFS were 1.2, 3.0, and 1.1 years, respectively. Based on multivariable analyses, patients with ≥5 cm tumor size had poorer OS (versus < 5 cm; HR: 2.66; 95% CI: 1.16, 6.11; LR-p = 0.014). Importantly, the receipt of neo/adjuvant chemotherapy was the only factor associated with both a more favorable PFS (HR: 0.33; 95% CI: 0.17, 0.65; LR-p = 0.0002) and a more favorable MFS (median 1.33 years versus no chemo 0.5 years; HR: 0.35; 95% CI: 0.17, 0.73; LR-p = 0.005). Conclusions: Outcomes associated with intrathoracic SS remain poor. Factors associated with poorer outcomes include larger tumors and omission of chemotherapy in the management of localized disease. We recommend providing perioperative chemotherapy to all patients with ≥5 cm tumor size to improve progression and metastasis-free survival.

Treatment of Primary Pulmonary Synovial Sarcoma in a Low-Resource Country: A Case Report

Primary synovial sarcoma of the lung is a rare malignant cancer. The symptoms are nonspecific; they may not appear at all, so it is often diagnosed in the late stages. Moreover, accurate diagnosis requires a combination of the results of clinical evaluation, imaging, and histological examinations, since the results of these methods separately are not very specific and may lead to misdiagnosis. Given the rarity of this diagnosis, the therapy is not standardized. The preferred treatment regimen involves surgery combined with neoadjuvant or adjuvant radio- and chemotherapy. This case report describes a 67-year-old male patient who was diagnosed with pulmonary synovial sarcoma. Diagnosis was confirmed via computed tomography (CT) imaging and immunohistochemical (IHC) examination. After surgical removal, the patient underwent adjuvant radiotherapy.

Epidemiological trends of synovial sarcoma by primary tumor sites in the US from 2000 to 2020

BACKGROUND

Synovial sarcoma (SS) is a rare soft-tissue cancer. Existing literature encompasses Surveillance, Epidemiology, and End Results (SEER) data-based research on SS explaining the incidence-prevalence in general, by subtypes, and by age at diagnosis. Therefore, this study aimed to fill in the gap of knowledge about measures of disease occurrence and burden of SS by tumor site using the SEER database.

METHODS

In this cross-sectional study, primary SS patients were selected from SEER 17 Registries, Nov. 2021 (2000-2020) using ICD-O-3 codes 9040, 9041, 9042, and 9043. Patients with additional cancers were excluded. The primary tumor site was categorized into (1) head/neck, (2) internal thorax, (3) abdomen/pelvis, (4) upper extremity, and (5) lower extremity using ICD-10CM codes. Five outcomes were analyzed: age-adjusted incidence rate, 5-year limited-duration prevalence rate, incidence-based mortality, case-fatality rate, and overall survival.

RESULTS

From 2000-2020, the overall age-adjusted incidence rate was 0.15 per 100,000; the 5-year limited duration prevalence rate was 0.56 per 100,000; and the incidence-based mortality rate was 0.06 per 100,000 people. The case-fatality and 5-year OS rates were 39.2 % and 62.9 %, respectively. Lower extremity had the highest incidence of 0.07 (estimated 1166 cases), prevalence of 0.36 (estimated 224 cases), and mortality rate of 0.025 (estimated 429 deaths) per 100,000. The other four locations had much closer rates with each other. Intrathoracic SS had the highest case-fatality rate of 71.5 % (148/207) and lowest 5-year OS of 26.0 % (95 % CI: 19.6 %, 32.9 %) than other sites.

CONCLUSION

Based on the measures of disease frequency, the most common primary tumor site is the lower extremity, followed by the upper extremity, abdomen/pelvis, internal thorax, and head/neck. The least favorable primary location is the internal thorax. Those with a primary location of the upper extremity have the longest overall survival, followed by the head/neck, lower extremity, abdomen/pelvis, and internal thorax.

Primary thoracic synovial sarcomas: clinical profile and treatment outcomes of a rare entity managed at a tertiary care centre

Introduction

Primary thoracic synovial sarcoma (PTSS) is a rare malignancy presenting with varying clinical manifestations. There is a paucity of data with few studies dedicated to this unique subset of neoplasms. We present our findings from one of the largest real-world studies among patients with PTSS.

Methods

This is a single-centre, real-world study in patients with PTSS included between 2017 and 2023. Survival estimates were obtained by the Kaplan-Meier method and Cox regression analysis.

Results

24 patients with a median age of 34.5 years (range 16-54) presented with chest pain (n = 11, 45.8%) and dyspnea (n = 10, 41.6%). Predominant primary sites of disease were the lung (n = 12, 50%) and mediastinum (n = 6, 25%). The stage at presentation was unresectable locally advanced (n = 10, 41.6%), localised (n = 8, 33.3%) and metastatic (n = 6, 25%) with pulmonary metastases (n = 10, 62.5%) and pleural effusion (n = 4, 25%). 16 (66.6%) patients underwent surgical resection including 7 (43.8%) who received neoadjuvant chemotherapy (NACT). NACT was given in ten patients producing stable disease in 5 (50%) and partial response in 3 (30%) patients, respectively, with surgery performed in 7 (70%). 11 (62.5%) operated patients had a microscopically complete resection and 10 (41.6%) received postoperative radiotherapy. Anthracyclines were given in 23 (95.8%) patients in the first line, while pazopanib was the most common therapy in the second and third lines, respectively. At a median follow-up of 32 months (range 16.7-47.2), the median overall survival (OS) was 41 months (95% CI: 23.7-58.2) and 8 months (95% CI: 1-25.6) overall and in metastatic disease, respectively. Presentation with metastases (p = 0.01) and treatment with surgical resection (p = 0.005) were significantly associated with OS on univariate analysis.

Interpretation

The locally advanced nature of the disease at presentation signifies the need for early diagnosis and technically superior definitive therapies. The survival outcomes for metastatic disease remain poor and the need for novel therapies for advanced disease remains unmet so far.

Clinical trial registration

Not applicable.

Sarcoma of the Lung and Mediastinum

Primary sarcoma of the lung and mediastinum is rare. The diagnosis requires careful exclusion of sarcomatoid carcinoma, sarcomatoid mesothelioma, and metastases from extra-thoracic sites. This review summarizes the key morphologic, immunohistochemical, and molecular characteristics of sarcomas that are encountered in the lung and mediastinum. The tumor types discussed are synovial sarcoma, well-differentiated/dedifferentiated liposarcoma, myxoid pleomorphic liposarcoma, intimal sarcoma of the pulmonary artery, inflammatory myofibroblastic tumor, epithelioid hemangioendothelioma, primary pulmonary myxoid sarcoma, malignant peripheral nerve sheath tumor, Ewing sarcoma, and CIC-rearranged sarcoma. Relevant differential diagnoses are also addressed.

Extensive surgical resections for rare pleural neoplasms: a single-center experience with a yolk sac tumor and synovial sarcoma

BACKGROUND

Pleural neoplasms are rare and can be subdivided into pleural metastasis and primary pleural neoplasms. Non-mesothelioma primary pleural neoplasms are a diverse group of extremely rare pathologies.

CASE PRESENTATION

In this case series, we describe the presentation and management of two rare primary pleural neoplasms. A first case describes a primary pleural yolk sac tumor treated with neoadjuvant chemotherapy, extended pleurectomy decortication, and hyperthermic intrathoracic chemotherapy. In a second case we describe the management of a primary pleural synovial sarcoma by neoadjuvant chemotherapy and extrapleural pneumonectomy. A complete resection was obtained in both cases and the post-operative course was uncomplicated. No signs of tumor recurrence were noted during follow-up in the first patient. In the second patient a local recurrence was diagnosed 6 months after surgery.

CONCLUSION

Neo-adjuvant chemotherapy followed by extensive thoracic surgery, including hyperthermic intrathoracic chemotherapy, is a feasible treatment strategy for non-mesothelioma primary pleural neoplasms, but careful follow-up is required.

Mesenchymal tumours of the pleura: review and update

Primary mesenchymal tumours of the pleura are uncommon and can be diagnostically challenging due to their overlapping histopathologic and immunophenotypic features. Herein we discuss selected mesenchymal tumours of the pleura, including solitary fibrous tumour, calcifying fibrous tumour, desmoid fibromatosis, synovial sarcoma, schwannoma, malignant peripheral nerve sheath tumour, inflammatory myofibroblastic tumour, follicular dendritic cell sarcoma, epithelioid hemangioendothelioma, and desmoplastic small round cell tumour. We review their clinicopathologic characteristics, along with an update on the relevant immunohistochemical and molecular features.

Case report: Primary pleural low-grade fibromyxoid sarcoma in a 4-year-old boy with molecular confirmation

Low-grade fibromyxoid sarcoma (LGFMS) is a rare malignant fibroblastic tumor, principally affecting the deep tissues of the proximal trunk and extremities in young adults. However, primary pleural LGFMS is extremely rare, and only three cases have been reported in the previous English literature without genetic confirmation. Furthermore, the historical pleural LGFMS cases were all adults, and the primary pleural LGFMS in children has never been reported to date. Here, we presented a primary pleural LGFMS in a 4-year-old boy with detailed clinical, pathological, and molecular results. Histologically, the current tumor showed typical alternating collagenous and myxoid areas, containing spindled or oval tumor cells arranged in a whorled and short fascicular pattern. In some areas, the tumor cells exhibited moderate atypia, and mitotic figures were identified but without the identification of giant collagen rosettes. Immunohistochemically, all the neoplastic cells showed strong and diffuse positivity for MUC4. Genetically, FUS gene rearrangement was revealed by fluorescence in-situ hybridization (FISH), and subsequently, next-generation sequencing (NGS) and polymerase chain reaction (PCR) further demonstrated the FUS::CREB3L2 fusion transcript. To the best of our knowledge, this is the first case of primary pleural LGFMS with the identification of FUS gene rearrangement and FUS::CREB3L2 fusion in a 4-year-old child. Our study expands the age range of pleural LGFMS and highlights the combination of morphological, immunohistochemical, and molecular analyses in such challenging cases.

The Expression of Mucin-4 (MUC4) in Sarcomas Apart From Sclerosing Epithelioid Fibrosarcoma and Low-Grade Fibromyxoid Sarcoma

Background Low-grade fibromyxoid sarcoma (LGFMS) and sclerosing epithelioid fibrosarcoma (SEF) are two rare but aggressive soft tissue sarcomas that can be difficult to distinguish due to histopathological similarities. The present study examines the diagnostic capacities of mucin-4 (MUC4), a transmembrane mucin, in identifying different types of sarcomas and broadens its evaluation to include a wide range of sarcomas. Methods Immunohistochemical (IHC) examination of tissue samples from various sarcomas was performed using a mouse anti-MUC4 monoclonal antibody. IHC was conducted on 4-mm thick formalin-fixed paraffin-embedded tissue sections after pressure cooker antigen retrieval with a mouse anti-MUC4 monoclonal antibody. Results MUC4 was shown to be highly expressed in SEF (n=13) and LGFMS (n=10), while focal positivity in synovial sarcoma (n=1). Other sarcomas, such as malignant peripheral nerve sheath tumors, fibrosarcoma, leiomyosarcoma, liposarcoma, and myxofibrosarcoma, exhibited no expression (n=0). These findings are consistent with previous research and support MUC4 specificity as a SEF and LGFMS marker. This study provides information on the diagnostic efficacy of MUC4, particularly in the context of certain subtypes. It not only helps our understanding of these unique instances, but it also provides context for histopathological and IHC findings in soft tissue sarcoma. Furthermore, this study investigates the influence of age and gender on MUC4 expression in a range of sarcomas, which was typically understudied in the literature and found no relation with expression of MUC4. Conclusion In conclusion, this study adds to our understanding of soft tissue sarcomas by emphasizing the crucial role of MUC4 in certain sarcoma subtypes while acknowledging the complex variety of the sarcoma landscape. Further research is needed to understand the molecular mechanism that governs marker expression patterns, as well as the therapeutic implications.

A rare case of perineal synovial sarcoma

Synovial sarcoma is a malignant mesenchymal neoplasm that is frequently misdiagnosed due to its slow growth and small size. This tumor presents as a nonspecific heterogeneous mass on cross-sectional imaging. Biopsy and histopathological assessments are required to differentiate synovial sarcoma from other sarcoma subtypes and to define the tumor grade. This article presents the case of a 17-year-old male patient with perineal synovial sarcoma.

Mediastinal Synovial Sarcoma 14 Years After Talc Pleurodesis for Spontaneous Pneumothorax

A 36-year-old female with a remote history of spontaneous pneumothorax treated with talc pleurodesis presented with a large anterior mediastinal synovial sarcoma. The mass developed within a residual asymptomatic mediastinal space during a 2-year period. The patient underwent complete surgical resection and adjuvant chemoradiotherapy, which provide the best chance for survival. Although the cause of these tumors is unclear, this report may further delineate the natural history of this rare pathologic process.

Novel characteristics for immunophenotype, FISH pattern and molecular cytogenetics in synovial sarcoma

As a rare and highly aggressive soft tissue sarcoma, the new immunophenotype, atypical FISH pattern and relevant molecular cytogenetics of synovial sarcoma (SS) remain less known, although it is characteristically represented by a pathognomonic chromosomal translocation t (X; 18) (p11.2; q11.2). Methodologically, the morphology was retrospectively analysed by using H&E staining, and immunohistochemical features were investigated by using markers that have been recently applied in other soft tissue tumors. Moreover, FISH signals for SS18 and EWSR-1 break-apart probes were examined. Finally, cytogenetic characteristics were analysed via RT-PCR and Sanger sequencing. Consequently, nine out of thirteen cases that were histologically highly suspected as SS were finally identified as SS via molecular analysis. Histologically, nine SS cases were divided into monophasic fibrous SS (4/9), biphasic SS (4/9) and poorly differentiated SS (1/9). Immunohistochemically, SOX-2 immunostaining was positive in eight cases (8/9) and PAX-7 immunostaining was diffusely positive in the epithelial component of biphasic SS (4/4). Nine cases showed negative immunostaining for NKX3.1 and reduced or absent immunostaining for INI-1. Eight cases showed typically positive FISH signalling for the SS18 break-apart probe, whereas one case exhibited an atypical FISH pattern (complete loss of green signalling, case 2). Furthermore, the SS18-SSX1 and SS18-SSX2 fusion genes were identified in seven cases and two cases, respectively. The fusion site in 8 out of 9 cases was common in the literature, whereas the fusion site in case 2 was involved in exon 10 codon 404 in SS18 and exon 7 codon 119 in SSX1 (which has not been previously reported), which notably corresponded to the complete loss of green signalling in the FISH pattern. Additionally, FISH analysis of the EWSR-1 gene in nine SS cases demonstrated aberrant signalling in three cases that were recognized as a monoallelic loss of EWSR-1 (1/9), an amplification of EWSR-1 (1/9) and a translocation of EWSR-1 (1/9). In conclusion, SS18-SSX fusion gene sequencing is obligatory for a precise diagnosis of SS when dealing with a confusing immunophenotype and atypical or aberrant FISH signalling for SS18 and EWSR-1 detection.

Case report: Pulmonary synovial sarcoma in a long-term survivor of childhood Hodgkin lymphoma

Solid organ malignancies have been reported in survivors of Hodgkin lymphoma treated with chemoradiation; however, to the best of our knowledge no cases of pulmonary synovial sarcoma have been documented in the literature in this cohort. We herein provide a detailed description of synovial sarcoma occurring in the lung of a long-term survivor of childhood Hodgkin lymphoma. A 29-year-old female never smoker with past medical history of Hodgkin lymphoma diagnosed at the age of 7 years and treated with chemotherapy and radiation therapy was admitted for management of pneumothorax. Wedge lung resection of an ulcerated subpleural nodule revealed a malignant spindle cell tumor that based on light microscopic and immunohistochemical features was classified as monophasic synovial sarcoma. The diagnosis was further confirmed by identification of SS18 (SYT) rearrangement by fluorescence in situ hybridization and SS18-SSX1 gene fusion by RNA sequencing. The case documents a rare occurrence of synovial sarcoma in a long-term survivor of childhood Hodgkin lymphoma. While comprising a typical genetic profile for synovial sarcoma, the tumor had unusual histological features such as cystic and low-grade morphology. The case suggests that synovial sarcoma falls within an expanding spectrum of secondary malignancies following prior treatment of Hodgkin lymphoma.

Primary intrathoracic liposarcomas: A clinicopathologic and molecular study of 43 cases in one of the largest medical centers of China

Introduction

Primary intrathoracic liposarcoma is extremely rare, and most published series lack genetic analyses. The aim of our study is to better understand the clinicopathologic and genetic features of these rare lesions.

Materials and methods

Forty-three primary intrathoracic liposarcomas were identified and most cases were analyzed by systematic genetic studies, including fluorescence in situ hybridization (FISH), whole-exome sequencing (WES), and Sanger sequencing.

Results

This series included 27 males and 16 females (ratios, 1.68:1) aged 24-73 years (median, 53 years). Tumors mainly occurred in the mediastinum (n=23, 53.5%), followed by pleural cavity (n=16, 37.2%) and lung (n=4, 9.3%). The study included 21 well-differentiated liposarcomas (WDLs), 19 dedifferentiated liposarcomas (DDLs), 2 myxoid pleomorphic liposarcomas (MPLs) and 1 pleomorphic liposarcoma (PL), without identification of myxoid liposarcoma. FISH analysis identified MDM2 amplification in 17 of 18 WDLs (94.4%) and all DDLs (16/16, 100.0%). The MDM2-nonamplified WDL was CDK4-nonamplified but FRS2-amplified. WES and Sanger sequencing found somatic TP53 mutation in the 2 MPLs. Follow-up information was available for 33 of 38 cases (86.8%). Thirteen patients (39.4%) showed no evidence of disease, 10 patients (30.3%) were alive with disease, and 8 patients (24.2%) died of disease. Fourteen cases developed recurrence and 1 with metastasis.

Conclusions

WDL/DDL was the overwhelming subtype in this location, followed by MPL and PL. Analysis of the FRS2 gene, in combination with MDM2 and other genes of 12q13-15, may more precisely characterize WDL/DDLs. MPL is the most fatal subtype of this site. Further studies are needed to explore the role of TP53 in the pathogenesis of MPL.

Solitary primary pulmonary synovial sarcoma: A case report

BACKGROUND

Synovial sarcoma (SS) is an uncommon and highly malignant soft tissue sarcoma in the clinic, with primary pulmonary SS (PPSS) being extremely rare. Here, we describe the clinical characteristics, diagnosis, and treatment of a solitary PPSS case confirmed via surgical resection and fluorescence in situ hybridization (FISH).

CASE SUMMARY

A 33-year-old man was admitted because of intermittent coughing and hemoptysis for one month, with lung shadows observed for two years. Whole-body positron emission tomography-computed tomography (PET-CT) revealed a solitary mass in the upper lobe of the right lung, with uneven radioactivity uptake and a maximum standardized uptake value of 5.6. The greyish-yellow specimen obtained following thoracoscopic resection was covered with small multi-nodulated structures and consisted of soft tissue. Hematoxylin and eosin staining revealed spindle-shaped malignant tumor cells. Immunohistochemistry indicated these tumor cells were CD99 and BCL-2-positive. Furthermore, the FISH test revealed synovial sarcoma translocation genetic reassortment, which confirmed the diagnosis of SS.

CONCLUSION

PPSS is extremely rare and tends to be misdiagnosed as many primary pulmonary diseases. PET-CT, histologic analysis, and FISH tests can be used to differentiate PPSS from other diseases. Surgical resection is regularly recommended for the treatment of solitary PPSS and is helpful for improving the prognosis.

Primary Pleuropulmonary Synovial Sarcoma: Report of Two Cases and a Comprehensive Review of the Literature

Primary sarcomas of the lung represent less than 0.5% of all primary lung tumors and comprise a heterogeneous group of malignancies including synovial sarcoma (SS). Primary pleuropulmonary SS has non-specific presentations, such as chest pain, shortness of breath and cough, and its associated imaging features resemble those of other intrathoracic malignancies. The diagnosis of these tumors needs to be confirmed by cytogenetic and molecular studies. Here, we describe two rare cases of primary pleuropulmonary SS who were admitted to our hospital. We also provide a concise review of clinical, radiological, and histopathological characteristics of pleuropulmonary SS after exploring 168 studies (415 corresponding patients) that were identified through a literature search.

The value of multidisciplinary team (MDT) management in the diagnosis and treatment of primary intrathoracic synovial sarcomas: a single-center experience

Background

Synovial sarcoma (SS) is a rare malignant soft tissue tumor. Primary intrathoracic SS is extremely rare, with limited diagnosis and treatment experiences. The aim of our study was to retrospectively study the clinicopathological characteristics, treatment and prognosis of primary intrathoracic SS and the impact of multidisciplinary team (MDT) management in diagnosis and treatment on patient prognosis.

Methods

The clinical and pathological characteristics, treatment, survival and prognosis of patients with primary intrathoracic SS admitted to the National Cancer Center from January 1999 to December 2018, as well as MDT intervention during diagnosis and treatment, were retrospectively analyzed.

Results

Thirteen patients were enrolled, including 7 (53.8%) males and 6 (46.3%) females, with primary intrathoracic SS in the lung (8/13, 61.5%), mediastinum (4/13, 30.8%) and pleura (1/13, 7.7%) as confirmed by morphological observation, immunohistochemical (IHC) staining and fluorescence in situ hybridization (FISH). Overall, 10/13 (76.9%) patients underwent surgery, and 6/10 (60.0%) received postoperative adjuvant therapy. Only 23.1% of patients received nonsurgical therapy. The MDT discussed and managed seven patients before and/or after surgery and one patient who did not undergo surgery. The estimated 3- and 5-year overall survival (OS) rates were 50.0% and 30.0%, respectively. Patients who were managed by an MDT had a longer median OS time than those who were not (46.0 vs. 18.0 months). Age (P=0.018), tumor location (P=0.029), and Ki-67 (P=0.020) were found to be significantly related to OS.

Conclusions

Monophasic morphology and fusion gene characteristics are the main features for the diagnosis of primary intrathoracic SS. MDT management can help obtain accurate diagnoses and provide reasonable therapeutic options.

BRAF V600E mutation is a potential therapeutic target for a small subset of synovial sarcoma

Synovial sarcoma (SS) is an aggressive tumor that most often affects the deep soft tissues in young adults. Intrathoracic SS is rare and is associated with poor outcome, highlighting the urgent need for a novel therapeutic strategy. In the process of clinical sequencing, we identified two patients with intrathoracic SS harboring the BRAF V600E mutation. The patients were women aged 32 and 23 years, and both presented with SS18-SSX2-positive monophasic SS in the thoracic cavity. BRAF V600E mutations were detected by next generation sequencing, and validated immunohistochemically by diffuse intense positivity to BRAF V600E mutation-specific antibodies. The phosphorylated ERK (pERK) immunohistochemistry result was also positive. One patient received a combination therapy of dabrafenib and trametinib, which led to tumor shrinkage. However, the tumor growth progressed 7.5 months later with an additional NRAS Q61K mutation. Immunohistochemical screening of 67 archival SS tumor samples failed to identify additional samples with BRAF V600E mutation. However, 32% of BRAF V600E-negative cases was positive for pERK, and one of the six tumors showing the highest pERK expression harbored an FGFR2-activating mutation. This is the first report of targetable BRAF mutation in a small subset of SS. Our study suggests involvement of the mitogen-activated protein kinase pathway and the potential clinical implication of BRAF mutation screening in SS.

Rare monophasic mediastinal pleural synovial sarcoma diagnosed via endobronchial ultrasound-transbronchial needle aspiration

The mediastinum is a rare site for occurrence of a primary synovial sarcoma (SS) with very few cases reported in the literature. The diagnosis so far has been achieved mainly via open surgery, with only three reported cases diagnosed via endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA), however, none of those were located at the posterior mediastinum, without showing any oesophageal or endobronchial involvement. To our knowledge, this is the first reported case of a monophasic primary pleural mediastinal SS purely involving the posterior mediastinum without oesophageal or endobronchial component, diagnosed via EBUS-TBNA.

Pediatric thoracic mass lesions: Beyond the common

Thoracic mass lesions can be categorized as originating in one of the three major compartments: a) chest wall and pleura, b) lung parenchyma and airways, c) mediastinum. While some of these, such as lymphoma, are common in both children and adults, others are rare and unique to childhood. The goal of this review is to familiarize radiologists with unusual but distinctive mass lesions of the pediatric thorax.

Is TLE1 Expression Limited to Synovial Sarcoma? Our Experience at Shifa International Hospital, Pakistan

Introduction: Synovial sarcoma (SS) accounts for 10-15 percent of adult soft tissue sarcomas. Transducin-like enhancer of split 1 (TLE1), a transcriptional repressor, is essential in hematopoiesis, neuronal differentiation, and terminal epithelial differentiation. TLE1 proteins inhibit Wnt signaling and other cell fate determination signals, and so have an established role in repressing differentiation. TLE1 has recently been shown to be a highly sensitive and relatively specific marker of SS.

Materials and methods: Study design is retrospective, descriptive. A total of 25 cases of SS and 28 of soft tissue lesions were retrieved from the record. TLE1 (clone 1F5) expression was evaluated and scored as negative (<5% of cells positive), 1+ (5-25% of cells positive), 2+ (26-50% of cells positive), or 3+ (>50 % of cells positive).

Result: Twenty-four out of twenty-five (96%) cases of SS showed 3+ TLE1 expression. One (4%) case of poorly differentiated SS showed 2+ positivity. 3+ TLE1 positivity was seen in one (100%) case each of infantile fibrosarcoma and low-grade fibromyxoid sarcoma, while two cases (100%) of schwannoma also showed 3+ positivity. All cases of solitary fibrous tumor) (n=2), clear cell sarcoma of tendons and aponeurosis (n=2), embryonal rhabdomyosarcoma (n=1), and de-differentiated liposarcoma (n=2) showed 2+ positivity. 1+ positivity was seen in alveolar soft part sarcoma (n=2), Ewing's sarcoma (n=4), undifferentiated pleomorphic sarcoma (n=1), myxoid liposarcoma (n=1) and malignant peripheral nerve sheath tumor (n=1). TLE1 was negative in all cases of chordomas (n=2), lipomas (n=2), nodular fasciitis (n=2), malignant perivascular epithelioid cell tumor (n=1) and dermatofibrosarcoma protuberans (n=1).

Conclusion: TLE1 may be a reliable immunostain for diagnosing SS, but its expression is not limited to SS. Its expression should be interpreted in the light of morphological features and a panel of antibodies.

Primary pleural synovial sarcoma with repeated resection leading to long-term survival

Primary pleural synovial sarcoma is a malignant tumour and thought to be more aggressive than synovial sarcoma which occurs in extremities. Its treatment strategy has not been fully established because of its rarity. We report a primary pleural synovial sarcoma case which achieved a long-term survival with repeated surgery of recurrent pleural tumour. A 39-year-old man presented with a gradually enlarged tumour in the left hemithorax. The tumour was resected and diagnosed as primary pleural synovial sarcoma. The tumour was slowly growing and repeatedly recurrent in the left pleura. The surgical resections for the recurrent tumours were performed 6 years and 11 years after the initial surgery. Intriguingly, recurrent tumour which developed after second surgery exhibited temporally spontaneous regression. Our patient remains alive 12 years after the initial surgery. Repeated resection of metastatic lesion can achieve long survival in primary pleural synovial sarcoma.

A second primary synovial sarcoma of pleural developed nine-years after the first synovial sarcoma of plantar pedis: a case report and review of literature

Synovial sarcoma is a rare cancer which occurs primarily in the extremities of young adults. Among them, synovial sarcoma of pleura is a very rare type. Only less than 50 cases have been reported in the literature. Here we report a unique case of synovial sarcoma of pleural. The patient was a 53-year-old man complained of cough, hemoptysis and shortness of breath for 5 month. Chest CT scan revealed a large mass lesion in the left lung, and several metastatic legions in both lungs. No other organs were involved at the time of examination. The patient had synovial sarcoma at right plantar nine years ago. The tumor was surgically removed and followed with radiotherapy for half a month. The patient did regularly follow-up examinations for 5 years, and no metastasis and recurrence were found. He was in remission for 9 years. The patient was admitted in hospital, and the fine needle biopsy and histology studies supported the diagnosis of primary synovial sarcoma of pleural. Cytogenetic fluorescence in situ hybridization (FISH) confirmed the tumor had t(X;18) chromosomal translocation. He received 2 cycles of chemotherapy, and unfortunately tumor didn't response to the treatment. The patient was discharged without further treatment. This is the first case report that patient developed a second primary synovial sarcoma of pleural after nine years remission of the first primary synovial sarcoma in plantar.

Primary Synovial Sarcoma of the Mediastinum with Long-term Follow-up

Chest radiography showed a right posterior mass on the mediastinum of an 84-year-old woman. The mass had been growing gradually for four years. Surgical excision was performed, and a pathological examination found the mass to be consistent with primary synovial sarcoma (SS) of the mediastinum. To our knowledge, this is a rare case in which follow-up imaging was able to be performed over a period of four years. This disease is aggressive, and its early diagnosis is key to achieving a cure. It is important to consider primary SS in the differential diagnosis of a primary intra-thoracic tumor, even if the tumor grows slowly.

An overview on the differential diagnostics of tumors of the anterior-superior mediastinum: the pathologist's perspective

The thymus is the main organ in the (anterior) (pre-vascular) mediastinum, playing a central role in the maintenance of both cellular and humoral immunity. The function of the thymus has been long underlooked due to its involution starting during young adulthood and unawareness regarding its immunological function. A variety of primary tumors and inflammatory/reactive/disreactive processes occur in the mediastinum and may involve the anterior-superior compartment and the thymus. Maldevelopment processes also take place in the pre-vascular compartment mediastinum. Although infective diseases do not currently represent the main processes in western countries, they may represent a diagnostic challenge in developing countries. The purpose of this review is to provide a short overview of the main thymic cellular components, their tumors, pseudotumors, in order to provide insights into their clinical setting and the features which assist pathologists in their differential diagnosis (DD). Specific differential diagnostic points are provided, both for "solid" tumors as well as for haematological malignancies, together with a morphological overview of cases of concern that occur in the anterior mediastinum. The main immunohistochemical characteristics of neoplastic/non-neoplastic pathology and updated specific references are also provided.

Mesenchymal tumors of the lung: diagnostic pathology, molecular pathogenesis, and identified biomarkers

Lung cancers are mainly composed of epithelial tumors such as carcinomas. Since mesenchymal tumors that arise in the lung are very rare, they have garnered little attention. The 2015 World Health Organization (WHO) classification of lung tumors has undergone revision, not only for carcinomas but also for mesenchymal tumors. The current version now includes PEComatous tumors, myoepithelial tumors, and pulmonary myxoid sarcomas with EWSR1-CREB1 translocation as new disease entities. To date, no review article has comprehensively summarized what is known about pulmonary mesenchymal tumors in accordance with the latest WHO classification. In this review, we attempt to summarize the data about these tumors in line with the 2015 WHO classification (except for pediatric tumors), focusing on their diagnostic pathology, molecular pathogenesis, and identified biomarkers for differential diagnoses. We also address the recently recognized pulmonary mesenchymal tumors that have not yet been included in the WHO classification. An increased understanding of the molecular characteristics of pulmonary mesenchymal tumors has the potential to provide clinicians with the best therapeutic options for patients with these tumors.

Transducer-like enhancer of split 1 (TLE1) as a novel biomarker for diagnosis of synovial sarcoma correlates with translocation t(X;18): a study of 155 cases in China

Synovial sarcoma (SS) is a mesenchymal tumor of uncertain histogenesis which is defined by the translocation t(X;18). Transducer-like enhancer of split 1 (TLE1) as a new immunomarker for SS has offered an alternative to pathologists in distinguishing synovial sarcoma from other mesenchymal neoplasms, especially in limited molecular facilities. The main aim was to study the expression and diagnostic specificity and sensitivity of TLE1 in SS. We performed this immunohistochemical study on 155 SS (107 monophasic, 35 biphasic, and 10 poorly differentiated), 10 fibrosarcomas, 10 angiosarcomas, 10 epithelioid sarcomas, 10 Ewing sarcoma/PNETs and 8 malignant peripheral nerve sheath tumors (MPNST) using TLE1 immunomarker. Furthermore, in problematic cases (n=43), molecular confirmation was performed by fluorescent in situ hybridization (FISH) to detect the t(X;18) translocation. We correlated the TLE1 overexpression with the t(X;18) and other established biomarkers (CD117, CD56, cytokeratin AE1/AE3, EMA, CD99, BCL2, VIM, CD34, S100, Ki67, SMA). TLE1 expression was observed in 76.19% (112/147) of the SS, including 75.96% (79/104) of monophasic, 78.79% (26/33) of biphasic, and 70% (7/10) of poorly differentiated type. 65.99% (97/147) of SS cases showed a strong to moderate staining of TLE1. Other mesenchymal tumors showed very low or absent staining of TLE1 (P < 0.001). The overall sensitivity and specificity of TLE1 expression for the diagnosis of SS were 86.21% and 78.57%, respectively. Further molecular analysis showed that t(X;18) was clearly correlated with TLE1 expression (P=0.000). TLE1 is a specific and sensitive diagnostic immunomarker for SS and can be helpful to distinguish SS from other mesenchymal neoplasms.

Low-grade fibromyxoid sarcoma: a clinicopathologic and molecular study of 10 genetically confirmed cases

Low-grade fibromyxoid sarcoma (LGFMS) is a rare low-grade malignant fibroblastic tumor, harboring a characteristic FUS-CREB3L2 or FUS-CREB3L1 gene fusion. The authors presented 10 genetically confirmed cases in a Chinese population. To the best of our knowledge, the present series consists of the most genetically confirmed cases from a Chinese medical center in English literature. The clinical, histologic, immunohistochemical, and molecular features of all cases are reviewed. The age of the patients (7 females, 3 males) ranged from 4 to 58 years old (median, 26 y; mean, 27 y). Trunk (4/10, 40%) was the most common site. Microscopically, all the cases exhibited an admixture of myxoid nodules and fibrous zones. The tumor cells were deceptively bland and nuclear pleomorphism was observed in focal areas of one case. Immunohistochemically, neoplastic cells were focally reactive for EMA (1/9, 11.1%), and negative for S-100 protein, CD34, smooth muscle actin, and desmin (0/9). Of the 4 cases stained with MUC4, one showed focal expression and others were interpreted as indeterminate. Surgical excision was performed for all patients. Follow-up information was available for 8 cases, and none developed local recurrence or metastasis at last follow-up (mean 31 months). LGFMS is a distinctive low-grade malignant tumor. The diagnosis of this tumor might be very challenging and it is mistaken for many benign lesions. A combination of clinical studies, careful morphologic analysis, and a full panel of immunomarkers especially genetic studies is helpful in confirming the diagnosis. This tumor type is associated with favorable prognosis.

Unusual presentation of poorly differentiated primary pulmonary synovial sarcoma (PD-PPSS) diagnosed by EBUS-TBNA with cytogenetic confirmation-A diagnostic challenge

Poorly differentiated primary pulmonary synovial sarcoma (PD-PPSS) is a rare, aggressive neoplasm, which occurs in 0.5% cases of all lung malignancies. The diagnosis of PD-PPSS can be very challenging on cytology samples. We present here an unusual case of PD-PPSS diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), in the setting of known history of diffuse large B-cell lymphoma. Diff-Quik and Papanicolaou stains showed cellular specimen with clusters of highly atypical small round blue cells admixed with lymphoid elements; and some with denuded cytoplasm. Cell block further showed molding, crush artifact and atypical mitotic figures. A differential diagnosis based on extended immunohistochemical work-up was Ewing?s sarcoma/PNET versus poorly differentiated synovial sarcoma. Fluorescent in-situ hybridization (FISH) showed SYT gene rearrangement at 18q11.2. In this report, we describe the cytomorphological features, diagnostic pitfalls, challenges, potential mimics, and importance of acquisition of adequate material for the ancillary work-up on the cell block.

High expression of Ki-67 is an independent favorable prognostic factor for esophageal small cell carcinoma

BACKGROUND

The prognostic value of Ki-67 expression in small cell carcinoma of the esophagus (SCCE) has not been explored in any previous studies. Therefore, we conducted this retrospective study to investigate the prognostic role of Ki-67 in SCCE for the first time.

RESULTS

A total of 44 patients were included for analysis. The baseline clinicopathological data of these SCCE patients shared similar characteristics with previous studies. Ten patients were at stage I, 17 at stage II, and the remaining 17 were at stage III. Postoperatively, 23 patients received adjuvant therapy. Twenty-eight patients were found to have a high expression of Ki-67 (> 50%). After a median follow-up time of 54.8 months, the median survival time of those patients was 22.1 months. Early TNM stage, application of adjuvant therapy, and high expression of Ki-67 (Hazard Ratio = 0.314, 95% CI: 0.127-0.774; P = 0.012) were found to be favorable prognostic factors of patients with SCCE. In subgroup analysis, adjuvant therapy could only bring significant survival benefit for patients with high expression of Ki-67 (P = 0.008).

MATERIALS AND METHODS

Patients undergoing esophagectomy with lymphadenectomy for SCCE from January 2009 to January 2015 in our department were retrospectively analyzed. Data for analysis included demographic data, pathologic findings, tumor stage, adjuvant therapy, and survival time as well as Ki-67 index.

CONCLUSIONS

This study suggested that high expression of Ki-67 may not only serve as a favorable prognostic factor of SCCE but also an indication of providing adjuvant therapy for SCCE patients with surgical resection.