Primary cardiac tumors are rare and their incidence varies from 0.3% to 0.7% [1]. They are usually benign and only 25% are malignant. Primary cardiac sarcomas are even rarer with an incidence of 0.0001% in various autopsy series [2]. Angiosarcomas are the commonest accounting for about 33%-40%. Myxofibrosarcoma (MFS), pleomorphic sarcoma, and osteosarcoma are exceptionally rare primary cardiac tumors.MFS is an aggressive soft tissue neoplasm. It is often asymptomatic with extensive local invasion or distant metastases at detection. Although, a total of 31 cases have been reported, one with bone/osteoid differentiation has not been described [3]. To the best of our knowledge this is one of few reported cases of high grade primary cardiac MFS with areas of woven bone or osteoid matrix formation in the medical literature. Here, we share our case experience and problems encountered during diagnosis and management of this extremely rare histological subtype of MFS. Case reportA 62-year-old woman presented with the complaint of dyspnea on exertion (New York Heart Association class II) for the previous month. No significant past history was elicited. On examination, pulse was regular and blood pressure was 130/80 mmHg. On auscultation of chest, S1 was soft and S2 was normally split. There was an early diastolic plop sound after the S2 with a low pitched, mid-diastolic rumbling murmur (Grade II) over apex (mimicking mitral stenosis) without presystolic accentuation. The intensity of murmur changed in relation to patient's body position.Electrocardiogram (ECG) was normal. X-ray of chest showed cardiomegaly. N-terminal (NT)-proB-type natriuretic peptide (NT-proBNP) level was 120 pg/mL. Two-dimensional echocardiography (2D-ECHO) and transesophageal echocardiography (TEE) showed a large mass measuring 4.8 Â 3.5 cm almost filling the entire left atrium (LA). This mass was lobulated, sessile, having heterogenous echogenicity with areas of dense calcification and cystic degener-