Synovial sarcoma is a rare mesenchymal tumour that mainly presents in adolescents and adults younger than 30. It is characterised by a translocation between chromosomes X and 18, which leads to the expression of SS18:SSX fusion proteins. Although it can arise from various soft tissues, the lower limb is the most common site of origin. Pericardial synovial sarcoma is an extremely rare primary malignant tumour of the heart with an unclear prognosis. There are only a few cases reported from Pakistan. Here, we report a case of a 33-year-old male who presented with symptoms of chest pain and shortness of breath. The case was discussed in a multi-disciplinary tumour board and the surgeons deferred surgery as it was associated with high-risk mortality and was also refused by the patient so he was first managed with systemic chemotherapy to which he responded very well and was shifted to maintenance therapy using Pazopanib (small molecule tyrosine kinase inhibitors), to which he initially responded but later symptoms started to worsen and there was an interval increase in the size of the lesion. This report aims to share the diagnosis and management of this patient.