Primary pericardial synovial sarcoma: diagnosis of recurrence via multimodal imaging—a case report

Abstract

Background Primary pericardial synovial sarcoma (PSS) is an extremely rare malignancy. Diagnosis and management primarily rely on multimodal imaging, with definitive diagnosis typically requiring a biopsy for histopathological confirmation. Although no established treatment protocol exists, complete tumour resection followed by adjuvant chemotherapy and radiotherapy is often considered. Case summary A 68-year-old man presented with 1 month of shortness of breath and no significant medical history. Initial examination revealed cardiomegaly, a large pericardial effusion, and a solid mass adjacent to the right atrium. Multimodal imaging, including contrast-enhanced computed tomography and positron emission-T, identified a pericardial mass with metabolic activity. A thoracoscopic biopsy revealed atypical spindle-shaped cells, confirming the diagnosis of synovial sarcoma. This led to total tumour excision and lymph node dissection. Eighteen months post-surgery, imaging revealed recurrence, and the mass from the pericardium near the superior vena cava was resected via thoracotomy. Histopathological examination confirmed recurrent synovial sarcoma. Postoperative chemotherapy was administered; however, lung metastases developed, leading to further treatment 12 months post second surgery. Discussion PSS is associated with poor prognosis and a high recurrence risk, highlighting the importance of regular follow-up imaging. While complete surgical resection remains the primary treatment, adjunct therapies may improve outcomes. This case underscores the need for multimodal imaging in diagnosing and monitoring PSS.