Whole-exome sequencing in primary pulmonary synovial sarcoma misdiagnosed as mesothelioma: A case report and literature review

Our plain-English summary of Whole-exome sequencing in primary pulmonary synovial sarcoma misdiagnosed as mesothelioma: A case report and literature review, by D. Wu, H. Zhang, X. Li, et al (Thoracic Cancer, 2023).

The study

• Authors: D. Wu, H. Zhang, X. Li, J. Liu, M. Liu, H. Liu, M. Dong, J. Chen
• Journal: Thoracic Cancer
• Published: 2023;14(16):1520-1529
• Type of article: Review, Case report
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Synovial sarcoma is a highly malignant tumor that accounts for 10% of all soft tissue sarcomas. Primary pulmonary synovial sarcoma (PPSS) is extremely rare, and its prognosis is poor. A diagnosis is usually established after other primary lung malignancies or metastatic extrathoracic sarcomas have been excluded. Therefore, it is often misdiagnosed. In this study, we report the case of a 38-year-old woman who was misdiagnosed as having pleural mesothelioma and finally endured surgery to remove the tumor. The tumor showed SYT-SSX fusion transcripts and was diagnosed as PPSS after combining histopathological and immunohistochemical analyses. Finally, we determined some biomarkers through whole-exome sequencing (WES) to improve the diagnosis and treatment strategies.

© 2023 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

In plain English

This was a case report, with a literature review, of primary pulmonary synovial sarcoma, a rare lung cancer. The patient, a 38-year-old woman treated in Tianjin, China, had no smoking, asbestos exposure or family cancer history. She had had surgery for a spontaneous pneumothorax at age 19. A CT scan showed a 13-cm pleural-based mass in the right middle lobe. After a needle biopsy she was misdiagnosed with malignant mesothelioma and given pemetrexed, then pemetrexed with carboplatin; the tumor did not go into remission. After surgery, a FISH test showed an SYT gene split signal in 90% of tumor cells, and she was diagnosed with primary pulmonary synovial sarcoma. Whole-exome sequencing found several gene changes and a low tumor mutational burden (1.6 muts/Mb). She took anlotinib from three months after surgery. Progression-free survival was about nine months after surgery, and she died on June 24, 2019. Based on this case, the authors concluded that anlotinib could be a potential treatment option for advanced patients. They also said that, if necessary, broader immunohistochemistry and gene testing should be used to reduce misdiagnosis.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case report of one patient, with a review of the literature on pulmonary synovial sarcoma
• Who was studied: One 38-year-old woman. She was first seen at a local hospital and then transferred to the authors' hospital (Tianjin Medical University General Hospital, China). She died in June 2019.
• Exposure: No occupational or environmental exposure was studied. The patient had no smoking, asbestos exposure or family history of malignancy. Her past history included spontaneous pneumothorax surgery at age 19.
• Main results:
  • A chest CT at the local hospital showed a 13-cm pleural-based mass in the right middle lobe.
  • Based on the core needle biopsy, the patient was misdiagnosed with malignant mesothelioma. She received pemetrexed alone, after which the tumor slightly enlarged. She then received two cycles of pemetrexed with carboplatin, after which the tumor was not in remission.
  • Surgery through a right thoracotomy removed the right upper and middle lobes, part of the right lower lobe and parts of the third and fourth ribs.
  • FISH showed an SYT split signal in 90% of tumor cells, indicating a chromosome translocation of the SYT gene.
  • Whole-exome sequencing of the tumor found seven gene amplifications: CDK4, AKT2, CCND2, MDM2, NTRK1, AXL and KRAS. It also found an AFF3 gene missense change. The tumor mutational burden was low at 1.6 muts/Mb.
  • Postoperative genetic tests indicated low sensitivity of the tumor to the chemotherapy drugs given before surgery.
  • The patient refused chemotherapy or radiotherapy and was given anlotinib (8 mg daily) starting three months after surgery. Side effects included hypertension and constipation. Progression-free survival was about nine months after surgery.
  • PET-CT in February 2019 showed multiple metastases. Her condition deteriorated in June 2019, and she died on June 24, 2019.
• The authors' conclusion: Based on the progression-free survival in this case, the authors concluded that anlotinib could be a potential treatment option for advanced patients. They also concluded that young patients who have had pneumothorax surgery may have occult pulmonary synovial sarcoma. Finally, they said that, if necessary, broad immunohistochemistry and gene testing should be used to reduce misdiagnosis.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Synovial Sarcoma, Mesothelioma, Sarcoma, Prognosis, Pleural Mesothelioma, Biomarker.

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• Synovial sarcoma of the pleura and its differentiation from other primary pleural tumours: a clinicopathological and immunohistochemical review of three cases — A.G. Nicholson, P. Goldstraw, et al. (1998)
• TLE1 is expressed in the majority of primary pleuropulmonary synovial sarcomas — L.S. Lino-Silva, J.P. Flores-Gutiérrez, et al. (2011)
• NY-ESO-1 expression in synovial sarcoma and other mesenchymal tumors: significance for NY-ESO-1-based targeted therapy and differential diagnosis — J.P. Lai, P.F. Robbins, et al. (2012)
• Pleural malignant mesothelioma versus pleuropulmonary synovial sarcoma: a clinicopathological study of 22 cases with molecular analysis and survival data — S. Klebe, S. Prabhakaran, et al. (2018)

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