Liposarcoma is the second most common type of soft tissue malignancy in adults. They are malignant tumours with a mesenchymal origin. Mediastinal liposarcoma accounts for <1% of mediastinal tumours and 2% of liposarcoma. We report a patient with mediastinal liposarcoma who presented with cardiac tamponade, 25 years after the initial liposarcoma in the popliteal fossa.