A pulmonary mass extending into the left atrium through the pulmonary vein: a rare diagnosis with an unusual origin.

Introduction: Myxofibrosarcoma usually occurs in the extremities of middle-aged to older adults. Metastatic myxofibrosarcomas generally emerge in the lung. In this case report, we aim to present a case of primary pulmonary myxofibrosarcoma with tumor thrombus extending into the left atrium without pulmonary vein or atrial invasion.