Primary chondroblastic osteosarcoma of the mitral valve without metastasis

Primary osteosarcomas of the heart are extremely rare entities, with common subtypes including osteoblastic, chondroblastic and fibroblastic subtypes. We describe a case of a 53-year-old female with history of treated breast cancer who presented with progressive dyspnea on exertion. A pulmonary artery protocol CTA demonstrated an anterior mitral leaflet lobulated mass without an osteoid or chondroid matrix. Additional cross-sectional imaging demonstrated no evidence of distant metastasis. The mass was surgically excised with pathology demonstrating a malignant neoplasm with spindle cells, bone, cartilage and rare osteoid, most consistent with a high grade chondroblastic osteosarcoma. After the expected postsurgical recovery, the patient was initiated on adjuvant therapy consisting of ifosfamide and etoposide and is currently disease free for 9 years now. Review of literature demonstrates that cardiac primary osteosarcomas typically involve the left atrium. Imaging usually shows a lobulated or irregular mass with heterogenous attenuation/enhancement and, counterintuitively, a lack of a calcified matrix. Complete surgical excision is challenging leading to poor prognosis, even in cases undergoing post-surgical chemotherapy. Median survival has been reported as about 20 months.