Cardiac malignant tumours are extremely seldom in clinic, especially primary cardiac lymphomas. Due to the complexity of tumor, cardiac malignant tumours are characterized by multiple clinical and imaging manifestations. Consequently, cardiac malignant tumours may be easily misdiagnosed or neglected before histopathologic examinations. In this case, we reported a patient presented with intermittent bradyarrhythmia and was diagnosed as myxoma by imaging examinations, but he was eventually confirmed as primary cardiac lymphoma. This case highlights that diagnosis for cardiac myxoma should be caution even with sufficient imaging data.