Primary cardiac myxofibrosarcoma with osteoid differentiation mimicking a left atrial myxoma: A rare entity

Cardiac myxofibrosarcoma (MFS) is an uncommon entity. It is among the most challenging conditions to diagnose due to its rarity, high variability, and non-specific findings. These tumors often simulate left atrial myxoma or mitral stenosis at clinical presentation. Although, the definitive diagnosis of cardiac tumors depends on histopathological examination, various imaging techniques are also useful to study tumor characteristics to plan an appropriate treatment strategy. Here we highlight a case of primary cardiac MFS of left atrium (LA) showing areas of transition to undifferentiated pleomorphic sarcoma (UPS) with bone or osteoid formation, which is extremely rare and not well described. <Learning objective: Primary cardiac myxofibrosarcoma (MFS) is a rare and aggressive cardiac tumor. It is often confused with benign myxoma, leading to a delay in initiation of treatment. This delay can often lead to poor clinical outcomes. Our study will guide clinicians in early diagnosis, treatment, and counseling of patients with this rare entity. Echocardiography, together with magnetic resonance imaging, histology, and immunohistochemistry are essential in the diagnosis of MFS.>.