Primary Pulmonary Myxoid Sarcoma Research Articles

Primary Pulmonary Myxoid Sarcoma in an Asymptomatic 47-Year-Old Female

Primary Pulmonary Myxoid Sarcoma in an Asymptomatic 47-Year-Old Female

Primary pulmonary myxoid sarcoma in the interlobar fissure of the left lung lobe: a case report

BackgroundPrimary pulmonary myxoid sarcoma (PPMS) is a rare, low-grade malignant tumor, constituting approximately 0.2% of all lung tumors. Despite its rarity, PPMS possesses distinctive histological features and molecular alterations, notably the presence of EWSR1-CREB1 gene fusion. However, its precise tissue origin remains elusive, posing challenges in clinical diagnosis.Case demonstrationA 20-year-old male patient underwent a routine physical examination 6 months prior, revealing a pulmonary mass. Following surgical excision, microscopic evaluation unveiled predominantly short spindle-shaped tumor cells organized in a fascicular, beam-like, or reticular pattern. The stromal matrix exhibited abundant mucin, accompanied by lymphocytic and plasma cell infiltration, with Russell bodies evident in focal areas. Immunophenotypic profiling revealed positive expression of vimentin and epithelial membrane antigen in tumor cells, whereas smooth muscle actin and S-100, among others, were negative. Ki-67 proliferation index was approximately 5%. Subsequent second-generation sequencing identified the characteristic EWSR1-CREB1 gene fusion. The definitive pathological diagnosis established PPMS. The patient underwent no adjuvant chemotherapy or radiotherapy and remained recurrence-free during a 30-month follow-up period.ConclusionsWe report a rare case of PPMS located within the left lung lobe interlobar fissure, featuring Russell body formation within the tumor stroma, a novel finding in PPMS. Furthermore, the histomorphological characteristics of this case highlight the diagnostic challenge it poses, as it may mimic inflammatory myofibroblastic tumor, extraskeletal myxoid chondrosarcoma, or hemangiopericytoma-like fibrous histiocytoma. Therefore, accurate diagnosis necessitates an integrated approach involving morphological, immunohistochemical, and molecular analyses.

Molecularly Defined Thoracic Neoplasms.

Molecularly defined neoplasms are increasingly recognized, given the broader application and performance of molecular studies. These studies allow us to better characterize these neoplasms and learn about their pathogenesis. In the thorax, molecularly defined neoplasms include tumors such as NUT carcinoma, SMARCA4-deficient undifferentiated tumor (DUT), primary pulmonary myxoid sarcoma with EWSR1::CREB1 fusion, hyalinizing clear cell carcinoma, and SMARCB1-deficient neoplasms. Overall, these tumors are rare but are now more often recognized given more widely available immunostains such as NUT (NUT carcinoma), BRG1 (SMARCA4-DUT), and INI-1 (SMARCB1-deficient neoplasm). Furthermore, cytogenetic studies for EWSR1 to support a hyalinizing clear cell carcinoma or primary pulmonary myxoid sarcoma are, in general, easily accessible. This enables pathologists to recognize and diagnose these tumors. The diagnosis of these tumors is important for clinical management and treatment. For instance, clinical trials are available for patients with NUT carcinoma, SMARCA4-DUT, and SMACRB1-deficient neoplasms. Herein, our current knowledge of clinical, morphologic, immunophenotypic, and molecular features of NUT carcinomas, SMARCA4-DUT, primary pulmonary myxoid sarcomas, hyalinizing clear cell carcinoma, and SMARCB1-deficient neoplasms will be reviewed.

Primary pulmonary myxoid sarcoma: A case report and review of the literature

Background: Primary pulmonary myxoid sarcoma is a very rare tumor, with less than 25 cases being described in the literature. When found in the bronchial tree, an R0 resection with post-operative follow-up is sufficient for curative treatment. We present a case of primary pulmonary myxoid sarcoma in a middle-aged man with an associated review of the literature to highlight this rare tumor. Case presentation: A 62-year-old man with a 40-pack-year smoking history presented to the thoracic surgery clinic for evaluation of a suspicious lung nodule. Pre-operative testing revealed a spiculated mass in the left upper lobe and the biopsy was non-diagnostic. The patient was taken for left upper lobectomy tri-segmentectomy with mediastinal lymph node dissection. Final pathology of the nodule revealed primary pulmonary myxoid sarcoma with an Ewing sarcoma breakpoint region 1 on chromosome 22 with activating transcription factor 1 (EWSR-ATF1) fusion transcript consistent with the diagnosis. Conclusion: Primary pulmonary myxoid sarcoma is an exceedingly rare sarcoma of the lung with less than 25 reported cases in the literature. This case report highlights our experience treating primary pulmonary myxoid sarcoma in a middle-aged man, and a review of current treatment recommendations in the available published literature.

A case of primary pulmonary myxoid sarcoma located in left lower lung

A case of primary pulmonary myxoid sarcoma located in left lower lung

P23.04 Primary Pulmonary Myxoid Sarcoma with EWSR1 Rearrangement: A Case Report

P23.04 Primary Pulmonary Myxoid Sarcoma with EWSR1 Rearrangement: A Case Report

HIGH GRADE SARCOMA WITH MYXOID FEATURES

SESSION TITLE: Medical Student/Resident Lung Cancer Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Primary pulmonary sarcomas (PPS) are a rare tumor entity in general and tend to be low grade tumors (1). Most sarcomas diagnosed in the lung are due to metastasis and follow an aggressive course (2,3,4,5). This case presents an aggressive, high grade, primary lung spindle cell sarcoma with myxoid features. CASE PRESENTATION: An 84-year-old female presented with chest pain and worsening dyspnea on exertion for two weeks. Imaging revealed a left posterior perihilar mass in her lung. The patient was stabilized and discharged with planned outpatient bronchoscopy with endobronchial ultrasound with transbronchial needle biopsy (EBUS-TBNA). Biopsies of left hilar adenopathy and the lower lobe mass were positive for malignant cells. Histologic analysis, including immunohistochemistry, revealed the tumor to be most consistent with Primary Spindle Cell Sarcoma of the lung not otherwise specified (NOS). The patient presented two weeks after the bronchoscopy with worsening dyspnea and cough. Repeat imaging of her chest revealed significant progression of the mass-like consolidation. The patient was admitted for further evaluation. She became hemodynamically unstable and required intubation with mechanical ventilation and vasopressor support. The patient’s malignancy was determined staged as IVA, M1a. The patient's clinical status continued to rapidly deteriorate. The patient and her family decided to pursue comfort cares and the patient died shortly thereafter. DISCUSSION: Primary Pulmonary Myxoid Sarcoma (PPMS) is a similar tumor entity to PPS. Histologically, PPMS is characterized by polygonal tumor or spindle cells in a myxoid stroma with some atypia (4,6). The time of symptom onset to expiration was 61 days. This case describes a tumor with both aggressive and non-aggressive characteristics. Tissue analysis of this tumor revealed no cytological atypia or necrosis. Feng et al found that tumors in the respiratory system have a poorer prognosis. Tumor size is a prognostic indicator in PPS and tumors over 5 cm had a poorer overall survival (8). This tumor at symptom onset was 8 cm. The size and location of this tumor may have contributed to its aggressiveness and prognosis. Surgical resection is the treatment of choice for PPS and PPMS (3,7,8,9). CONCLUSIONS: There have been few case reports of this type of tumor being an aggressive and high-grade tumor. Given the aggressive nature, physicians need to be aware of this entity so appropriate guidance to patients and families can be provided. Furthermore, more research needs to be done in order to better classify this type of primary sarcoma of the lung. Reference #1: 1.Prieto-Granada CN, Ganim RB, Zhang L, Antonescu C, Mueller J. Primary Pulmonary Myxoid Sarcoma: A Newly Described Entity—Report of a Case and Review of the Literature. International Journal of Surgical Pathology. 2017;25(6):518-525. doi:10.1177/1066896917706413. Reference #2: 2.Koelsche C, Tavernar L, Neumann O, et al. Primary pulmonary myxoid sarcoma with an unusual gene fusion between exon 7 of EWSR1 and exon 5 of CREB1. Virchows Archiv. 2019. doi:10.1007/s00428-019-02716-4. Reference #3: 3.Billingsley KG, Burt ME, Jara E, et al. Pulmonary Metastases From Soft Tissue Sarcoma. Annals of Surgery. 1999;229(5):602. doi:10.1097/00000658-199905000-00002. 4.Jeon YK, Moon KC, Park S-H, Chung DH. Primary pulmonary myxoid sarcomas with EWSR1-CREB1 translocation might originate from primitive peribronchial mesenchymal cells undergoing (myo)fibroblastic differentiation. Virchows Archiv. 2014;465(4):453-461. doi:10.1007/s00428-014-1645-z. 5.Von Mehren M, Randall L, Benjamin RS et al. Soft tissue sarcoma version 2.2018. The Journal of the National Comprehensive Cancer Network. 2018;16(5): 536-563. doi: 10.6004/jnccn.2018.0025 6.Thway K, Nicholson AG, Lawson K, et al. Primary Pulmonary Myxoid Sarcoma With EWSR1-CREB1 Fusion. The American Journal of Surgical Pathology. 2011;35(11):1722-1732. doi:10.1097/pas.0b013e318227e4d2. 7.Feng L, Wang M, Yibulayin F, et al. Spindle cell sarcoma: a SEER population-based analysis. Scientific Reports. 2018;8(1). doi:10.1038/s41598-018-23145-4. 8.Spraker MB, Bair E, Bair R, Connell PP, Mahmood U, Koshy M. An Analysis of Patient Characteristics and Clinical Outcomes in Primary Pulmonary Sarcoma. Journal of Thoracic Oncology. 2013;8(2):147-151. doi:10.1097/jto.0b013e318277401f. 9.Bacha EA, Wright CD, Grillo HC, et al. Surgical treatment of primary pulmonary sarcomas1. European Journal of Cardio-Thoracic Surgery. 1999;15(4):456-460. doi:10.1016/s1010-7940(99)00045-7. DISCLOSURES: No relevant relationships by Jared Alberts, source=Web Response No relevant relationships by Alheli Arce Gastelum, source=Web Response No relevant relationships by Zachary DePew, source=Web Response No relevant relationships by Paul Millner, source=Web Response No relevant relationships by Kenneth Mueller, source=Web Response

Extrabronchial Primary Pulmonary Myxoid Sarcoma

Primary pulmonary myxoid sarcoma (PPMS) is a very rare condition of the lung that has been described recently. Here, we report the case of PPMS in an asymptomatic 30-year-old male patient. Chest CT showed a 45 × 53-mm mass located in the center of the left upper lobe, which was not detected during bronchoscopy. The tumor was safely and completely removed. Due to pathological studies of the tumor showing characteristics of a primary pulmonary myxoid sarcoma, neither adjuvant chemotherapy nor radiotherapy was prescribed postoperatively. The patient remained tumor-free during a follow-up of 4 years.

Primary pulmonary myxoid sarcoma with EWSR1-CREB1 fusion: a case report and review of the literature

BackgroundPrimary pulmonary myxoid sarcoma (PPMS) is an extremely rare lung sarcoma that is characterized in most cases by recurrent balanced chromosomal translocation t(2;22)(q33;q12) leading to the oncogenic fusion gene EWSR1-CREB1.Case presentationWe report a case of PPMS with molecular confirmation using fluorescence in situ hybridization (FISH) and DNA sequencing in a 45-year-old female patient. Computer tomography (CT) scanning revealed a peripheral circumscribed solid mass of 2.1 × 2 cm in the right lung superior lobe. Histologically, the tumor cells ranged from stellate, polygonal to chondrocyte-like or physaliferous-like, forming reticular network of delicate lace-like cellular strands and cords in abundant myxoid stroma. The tumor cell immunophenotype was positive for vimentin, EMA and negative for CK-pan, TTF-1, CAM5.2, S-100, calponin, SMA, desmin, ALK, CD31 and CD34. Molecular analysis demonstrated EWSR1-CREB1 gene fusion in this tumor. During 38 months of follow-up, the patient was alive with no clinical or radiological evidence of recurrence or metastasis.ConclusionPPMS is a rare low-grade sarcoma with distinct histological and genetic features. We add another case to the literature of this rare tumor and report for the first time occurrence of chondrocyte-like and physaliferous-like tumor cells in this tumor, thus enriching its morphologic and cytologic spectrum.

Sarcoma pulmonar mixoide primario asociado a traslocación EWSR1-CREB1 con micrometástasis locorregional

Primary myxoid pulmonary sarcoma is a rare entity with an endobronchial growth. Although it should be included in the differential diagnosis of other sarcomas, its prognosis is usually favorable. We present the case of a 51-year-old patient with a mesenchymal tumor in the right lung, diagnosed as a primary pulmonary myxoid sarcoma, positive for EMA, vimentine and with a Ki-67 less than 5%; FISH revealed a EWSR1-CREB1 translocation.

Hybrid bronchoscopic and surgical resection of endotracheal angiomatoid fibrous histiocytoma

BackgroundAngiomatoid fibrous histiocytoma (AFH) is a soft-tissue tumor that generally affects the extremities of children and young adults. AFH overlaps with primary pulmonary myxoid sarcoma (PPMS) and can occur in unusual locations.Case presentationWe present a case of a 22-year-old female with AFH in the distal trachea. In addition to describing the challenge in making a correct diagnosis of AFH, we describe the first case of successful hybrid bronchoscopic and surgical resection of endotracheal AFH. A staged removal procedure was required to quickly secure the airway, allowing a lower-risk elective distal tracheal resection through a cervical approach for complete resection. A more conventional, but more invasive, more painful and cosmetically less satisfying thoracotomy was avoided.ConclusionsA distal tracheal resection for AFH can be safely performed in young adults through a cervical approach with excellent follow-up results.

Primary pulmonary myxoid sarcoma with EWSR1-CREB1 fusion: report of a case

Primary pulmonary myxoid sarcoma with EWSR1-CREB1 fusion: report of a case

Clinicopathologic analysis of primary pulmonary myxoid sarcoma with EWSR1 translocation

Clinicopathologic analysis of primary pulmonary myxoid sarcoma with EWSR1 translocation

EWSR1 Fusions With CREB Family Transcription Factors Define a Novel Myxoid Mesenchymal Tumor With Predilection for Intracranial Location.

Recurrent gene fusions involving EWSR1 with members of the cAMP response element binding protein (CREB) family (ATF1 and CREB1) have been reported in a diverse group of tumors including angiomatoid fibrous histiocytoma (AFH), soft tissue and gastrointestinal clear cell sarcoma, primary pulmonary myxoid sarcoma, and hyalinizing clear cell carcinoma of salivary gland. We have recently encountered a group of 5 myxoid mesenchymal tumors positive for EWSR1 fusions with one of the CREB family member (ATF1, CREB1, and CREM), with histologic features distinct from any of the previously described pathologic entities. Tumors occurred in children or young adults (12 to 23 y; mean, 18 y), with equal sex distribution. All except 1 were intracranial (intra-axial, 2; meningeal, 2), whereas 1 was perirectal. Histologically, the tumors were well circumscribed, often lobulated, composed of uniform ovoid to round cells, and arranged in cord-like or reticular structures in a myxoid background. All except 1 displayed unique sunburst amianthoid fibers. Immunohistochemically, tumors were positive for epithelial membrane antigen (5/5; 4 focal, 1 diffuse) and desmin (3/5). A novel EWSR1-CREM fusion was identified by RNA sequencing in the perirectal tumor, which was further confirmed by fluorescence in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR). A second case with similar EWSR1-CREM fusion was identified by RT-PCR and FISH in a meningeal tumor. The remaining cases studied by FISH showed the presence of EWSR1-CREB1 fusion in 2 cases and EWSR1-ATF1 in 1. In conclusion, we report a distinct group of myxoid mesenchymal neoplasms occurring in children or young adults with a predilection for intracranial locations. Although the immunoprofile [epithelial membrane antigen (EMA), desmin] and the fusion type raise the possibility of a myxoid AFH, none of the typical histologic findings of AFH were present, suggesting a novel entity.

P3.01-025 Primary Pulmonary Sarcomas: An Entity Lost in Misdiagnosis: Topic: Morphology

Primary pulmonary sarcomas are very rare with an incidence rate of <0.5% of all lung malignancies. Their low incidence has impeded comprehensive evaluation of their association with smoking, definitive diagnostic and treatment-regimes. They are often misdiagnosed, both on radiology as well as on fine-needle-aspirate/small-biopsies. We present a series of primary pulmonary sarcomas diagnosed over the last two and a half years. All cases of primary pulmonary sarcomas (2014-2016) were retrieved and reviewed. A total of 21 sarcomas were identified. The most common was synovial sarcoma. Four exceptionally rare cases included pulmonary-artery intimal sarcoma, primary pulmonary myxoid sarcoma, malignant peripheral nerve-sheath tumor and follicular dendritic-cell sarcoma. The clinical and pathology details of which are provided in table1. The patients were distributed over a wide-age range (range: 9-65 years, median: 34 years) with a male-preponderance (M:F=2.2:1). Radiological features were non-specific except in case1 (table1). Histopathology revealed spindle-cell tumor in all cases (figure1) and an extensive immunohistochemical-panel and cytogenetic testing was required to clinch the diagnosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT) This is a series of primary thoracic sarcomas with a highlight on four extremely rare cases which bring to light their unique clinical, radiological, histopathological and immunohistochemical findings. Awareness of such entities is essential for proper diagnosis, appropriate molecular-testing and treatment.

Primary pulmonary myxoid sarcomas with EWSR1-CREB1 translocation might originate from primitive peribronchial mesenchymal cells undergoing (myo)fibroblastic differentiation.

Primary pulmonary myxoid sarcoma (PPMS) is a very rare lung tumor that has recently been shown to harbor an EWSR1-CREB1 translocation. However, the histogenesis and biological behavior of PPMS remains unclear. To provide insight into the histogenesis of PPMS, we studied surgical resection specimens of four patients, two females and two males with an age range of 26 to 65 years, all non-smokers with mild anemia. The tumors, three of which are endobronchial, measured between 4 and 13 cm. One patient developed metastasis to the contra-lateral lung 7 months after resection. Other patients remained alive without tumor for 1.5, 10, and 13 years. Fluorescence in situ hybridization (FISH) analysis with a gene break apart probe showed an EWSR1 translocation in all cases. The EWSR1-CREB1 fusion transcript was detected in all cases by reverse-transcription PCR. Immunohistochemical staining showed diffuse positive staining of the tumor cells only for vimentin. Tumor cells expressed no other myoid, epithelial, endothelial, melanocytic, myoepithelial, or neuroendocrine markers, except for smooth muscle actin and epithelial membrane antigen, which were only focally positive in individual cases. Ultrastructural analyses revealed the presence in the tumor cells of intermediate filaments with focal densities along the sub-cytoplasmic membrane as well as dense plaques. These results suggest that PPMS exhibits myofibroblastic differentiation. We conclude that PPMS is an intermediate grade malignant lung tumor harboring EWSR1 translocations, which may originate from mesenchymal cells that undergo fibroblastic or myofibroblastic differentiation.

At the intersection of primary pulmonary myxoid sarcoma and pulmonary angiomatoid fibrous histiocytoma: observations from three new cases

HistopathologyVolume 65, Issue 1 p. 144-146 Correspondence At the intersection of primary pulmonary myxoid sarcoma and pulmonary angiomatoid fibrous histiocytoma: observations from three new cases Steven C Smith, Steven C Smith orcid.org/0000-0003-0982-4607 Department of Pathology, University of Michigan, Ann Arbor, MI, USAThese authors contributed equally to this study.Search for more papers by this authorNallasivam Palanisamy, Nallasivam Palanisamy Department of Pathology, University of Michigan, Ann Arbor, MI, USA Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USAThese authors contributed equally to this study.Search for more papers by this authorBryan L Betz, Bryan L Betz Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorScott A Tomlins, Scott A Tomlins Department of Pathology, University of Michigan, Ann Arbor, MI, USA Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA Departments of Urology and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorRohit Mehra, Rohit Mehra Department of Pathology, University of Michigan, Ann Arbor, MI, USA Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorLindsay A Schmidt, Lindsay A Schmidt Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorDavid R Lucas, David R Lucas Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorJeffrey L Myers, Jeffrey L Myers Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this author Steven C Smith, Steven C Smith orcid.org/0000-0003-0982-4607 Department of Pathology, University of Michigan, Ann Arbor, MI, USAThese authors contributed equally to this study.Search for more papers by this authorNallasivam Palanisamy, Nallasivam Palanisamy Department of Pathology, University of Michigan, Ann Arbor, MI, USA Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USAThese authors contributed equally to this study.Search for more papers by this authorBryan L Betz, Bryan L Betz Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorScott A Tomlins, Scott A Tomlins Department of Pathology, University of Michigan, Ann Arbor, MI, USA Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA Departments of Urology and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorRohit Mehra, Rohit Mehra Department of Pathology, University of Michigan, Ann Arbor, MI, USA Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorLindsay A Schmidt, Lindsay A Schmidt Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorDavid R Lucas, David R Lucas Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this authorJeffrey L Myers, Jeffrey L Myers Department of Pathology, University of Michigan, Ann Arbor, MI, USASearch for more papers by this author First published: 28 December 2013 https://doi.org/10.1111/his.12354Citations: 20 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume65, Issue1July 2014Pages 144-146 RelatedInformation

Extraskeletal Myxoid Chondrosarcoma-like Features in Metastasizing Lung Adenocarcinoma: Unique Morphological Changes after Chemo-radiotherapy

Lung cancer closely resembling Extraskeletal Myxoid Chondrosarcoma (EMC), called “primary pulmonary myxoid sarcoma (PPMS),” is an extremely rare tumor. This report is presented here of a unique case showing EMC-like changes only in metastases from conventional lung adenocarcinoma in an 81-year-old man. After lung tumor resection and chemo-radiotherapy, he underwent the resection of right adrenal metastasis composed of carcinomatous and EMC-like components. There were multifocal transitions between these components. He was treated with additional chemo-radiotherapy for newly developed liver and brain metastases, but he died 3.3 years after the initial surgery. Autopsy revealed EMC-like tumors, with or without minute adenocarcinomatous components, extensively involving widespread organs. Reverse transcription-polymerase chain reaction did not detect EWSR1- CREB1 fusion in the primary tumor or metastases. These features indicated that the current tumor was different from PPMS characterized by EWSR1-CREB1 fusion. We concluded that such EMC-like features represent morphological changes of metastatic lung adenocarcinoma. We believe that this possible occurrence should be recognized for accurate diagnosis of metastatic lung carcinoma.

The diversity of soft tissue tumours with EWSR1 gene rearrangements: a review

Many soft tissue sarcomas have chromosomal translocations with resultant formation of new fusion genes. Among the genes that can be rearranged, the EWSR1 gene has been identified as a partner in a wide variety of clinically and pathologically diverse sarcomas as well as some non-mesenchymal tumours. The former include Ewing sarcoma and similar (Ewing-like) small round cell sarcomas, desmoplastic small round cell tumour, myxoid liposarcoma, extraskeletal myxoid chondrosarcoma, angiomatoid fibrous histiocytoma, clear cell sarcoma of soft tissue and clear cell sarcoma-like tumours of the gastrointestinal tract, primary pulmonary myxoid sarcoma, extrasalivary myoepithelial tumours and sporadic examples of low-grade fibromyxoid sarcoma, sclerosing epithelioid fibrosarcoma and mesothelioma. EWSR1 is a 'promiscuous' gene that can fuse with many different partner genes, but sometimes this results in phenotypically identical tumours. EWSR1 can, conversely, partner with the same genes in morphologically and behaviourally different neoplasms. This paper reviews the diversity of the several soft tissue tumour types that are associated with rearrangement of the EWSR1 gene.

Primary pulmonary myxoid sarcoma with EWSR1‐CREB1 fusion, resembling extraskeletal myxoid chondrosarcoma: Case report with a review of Literature

Reported herein is an extremely rare case of primary pulmonary myxoid sarcoma (PPMS). A 31-year-old man presented with a 2.7 cm-sized pulmonary tumor surrounded by capsule-like fibrosis. The patient has been free of disease for 5.8 years after surgery. This tumor focally showed endobronchial features, and consisted of reticular cords of oval, short spindle, or polygonal cells with swollen vesicular nuclei accompanied by an abundant myxoid stroma, closely resembling extraskeletal myxoid chondrosarcoma. Tumor cells were diffusely positive for vimentin and focally positive for epithelial membrane antigen, but were negative for cytokeratin, TTF-1, Napsin A, S-100 protein, CD34, desmin, smooth-muscle actin, CD10, p63, calponin, h-caldesmon, c-kit, HMB-45, synaptophysin, or glial fibrillary acid protein. Our reverse transcription-polymerase chain reaction using the formalin-fixed, paraffin-embedded tumor tissues detected EWSR1-CREB1 fusion transcript, but could not demonstrate EWSR1-ATF1 fusion or EWSR1/TAF15/TFG-NR4A3 fusion. These findings indicate that the current tumor is an additional case of PPMS with EESR1-CREB1 fusion, recently reported by Thway et al. Some cases of PPMS can behave in an indolent manner.