Case report of an aggressive cardiac myxofibrosarcoma with rapid disease progression.

Background: Primary cardiac myxofibrosarcoma is an exceptionally rare malignant tumour, often asymptomatic until local invasion or distant metastasis occurs. Early diagnosis is challenging, and the prognosis is generally poor owing to high local recurrence and metastasis rates. Case Summary: We report the case of a 79-year-old woman who presented with neurological symptoms and multiple brain metastases. Imaging showed a broad-based exophytic mass obstructing the left pulmonary vein and extending into the left atrium. Surgical resection was conducted, and the diagnosis of myxofibrosarcoma was confirmed from histology. Despite surgery, the tumour recurred locally within days, and the brain metastases progressed. Considering the patient's deteriorating condition, no further treatment was initiated. She was then transferred to hospice care and died shortly thereafter. Discussion: Primary cardiac myxofibrosarcoma is an extremely rare malignancy with non-specific symptoms and poor prognosis owing to its aggressive biological behaviour. In this case, multimodal imaging showed features suggestive of malignancy, including an exophytic mass with a broad attachment base and heterogeneous signal intensity. Despite surgical resection, the tumour recurred rapidly, and brain metastases progressed. The tumour size, high histological grade, and delayed intervention are likely to contribute to poor clinical outcomes. Owing to their rarity, there are no standardized treatment guidelines for primary cardiac sarcomas. In this case, we reconfirmed the high-grade malignancy of the cardiac sarcoma through multiple computerized tomography scans conducted over a short period. Currently, the only method for prompt evaluation using multiple imaging modalities involves early surgical resection combined with adjuvant therapy to improve clinical outcomes.