Pericardial synovial sarcoma, a potential for misdiagnosis: clinicopathologic and molecular cytogenetic analysis of three cases with literature review

Our plain-English summary of Pericardial synovial sarcoma, a potential for misdiagnosis: clinicopathologic and molecular cytogenetic analysis of three cases with literature review, by Y. Cheng, W. Sheng, X. Zhou, et al (American Journal of Clinical Pathology, 2012).

The study

• Authors: Y. Cheng, W. Sheng, X. Zhou, J. Wang
• Journal: American Journal of Clinical Pathology
• Published: 2012;137(1):142-9
• Type of article: Case report, Review
• Cited by: 29 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Synovial sarcomas arising in unexpected locations may lead to diagnostic challenges. In this report, we describe 3 cases of synovial sarcoma that manifested clinically as primary pericardial lesions. All 3 cases occurred in men in their fourth decade. Fever, cough, chest pain, and chest distress were the most common symptoms. Histologically, 2 of the tumors were spindle cell monophasic, and 1 tumor was biphasic. By immunohistochemical studies, the tumor cells were positive for cytokeratins and epithelial membrane antigen. In addition, the tumor cells displayed focal immunoreactivity for calretinin, cytokeratin 5/6, and HBME-1, resulting in the initial interpretations of malignant mesotheliomas. None of the 3 cases were diagnosed correctly until subsequent molecular cytogenetic assays demonstrated the presence of SYT gene rearrangements. As there are overlapping morphologic features between pericardial synovial sarcoma and mesothelioma, molecular analysis is essential for differential diagnoses.

In plain English

This report described three men, aged 31, 31 and 38, with synovial sarcoma, a soft-tissue cancer, arising in the pericardium (the sac around the heart). The cases came from consultation files of a Shanghai cancer center, and the authors briefly reviewed published cases. Two tumors were spindle cell monophasic and one was biphasic. Before genetic testing, case 1's biopsy suggested a poorly differentiated sarcoma with suspected sarcomatoid mesothelioma, and its removed tumor was diagnosed as malignant mesothelioma; case 3's biopsy was read as sarcomatoid mesothelioma; case 2 was called an undifferentiated spindle cell sarcoma. In case 1, tumor cells partly stained for calretinin, cytokeratin 5/6 and HBME-1, markers also seen in mesothelioma. A genetic test (FISH) found SYT gene rearrangements in all three. One patient died 27 months after first presenting. Including these cases, the authors counted 14 pericardial synovial sarcomas reported in the English-language literature. The article did not study asbestos exposure. It noted that telling these tumors apart from mesothelioma matters partly because of compensation for occupational asbestos exposure. The authors concluded that definitive diagnosis should rest on molecular cytogenetic testing.

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 series of three patients with a brief literature review
• Who was studied: Three men (aged 31, 31 and 38) with synovial sarcoma arising in the pericardium, from the consultation files of the Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China; dates not given. The review covered 14 cases reported in the English literature, including these three.
• Exposure: No asbestos or other exposure was studied. Asbestos is mentioned only as one reason the distinction from mesothelioma matters (compensation for occupational asbestos exposure).
• Main results:
  • Among the three cases, two tumors were spindle cell monophasic and one was biphasic.
  • Case 1: the initial biopsy was diagnosed as poorly differentiated soft tissue sarcoma with suspicion of sarcomatoid mesothelioma.
  • Case 1: the subsequently excised tumor was diagnosed as malignant mesothelioma.
  • Case 3: the biopsy was initially interpreted as sarcomatoid mesothelioma.
  • Case 2: the pathologic diagnosis before molecular testing was undifferentiated spindle cell sarcoma.
  • In case 1, the epithelial structures of the tumor were partially positive for calretinin, cytokeratin 5/6 and HBME-1.
  • FISH testing showed SYT gene rearrangements in all three cases.
  • Case 2 died 27 months after initial presentation despite multimodality therapy.
  • Including the three present cases, 14 cases of pericardial synovial sarcoma had been reported in the English literature.
  • Across these reported pericardial synovial sarcoma cases (literature plus these three), median age at diagnosis was 33 years, average age was 39 years, and the range was 15 to 70 years.
  • Of 10 reviewed patients with follow-up information, 4 died of progressive disease, 4 were alive with unresectable disease, and 2 were alive with short follow-up.
• The authors' conclusion: The authors concluded that, because pericardial synovial sarcoma and mesothelioma overlap in appearance, the definitive diagnosis should be based on molecular cytogenetic testing, especially in difficult cases at unusual sites.
• Limitations the authors state:
  • The authors attribute the higher share of biphasic tumors among reported pericardial cases, compared with other sites, possibly to the small number of reported cases.

Topics

Medical terms in this study, explained in our Lexicon: Pericardial, Synovial Sarcoma, Misdiagnosis, Spindle Cell, Biphasic Mesothelioma, Epithelial Membrane Antigen (EMA), Calretinin, Cytokeratin 5/6.

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