A Rare Case of Osteosarcoma Metastasizing to the Heart in a 30-Year-Old Woman

Background: Cardiac metastases are among the rarest in oncology, usually silent and rarely attracting clinical attention, often discovered at autopsy.

Osteosarcoma is the most common malignant bone tumor, and its usual metastatic sites are the lung, bone, brain, soft tissue, and lymph nodes.

Cardiac metastases from osteosarcoma are exceptional.

Case Presentation: We report a rare case of cardiac metastases discovered in the presence of progressively worsening dyspnea, motivating the realization of transthoracic echocardiography, which revealed two large intracardiac masses located in the right cavities, with extensive thrombosis of the inferior vena cava.

A thoracic-abdominal-pelvic CT scan revealed a right coxo-pelvic mass suggestive of osteosarcoma. Ultrasound-guided biopsy with an anatomopathological study of the mass confirmed the diagnosis of chondroblastic osteosarcoma.

After neoadjuvant chemotherapy and surgical excision of the primary bone tumor and cardiac metastases, the anatomopathological study of the cardiac masses confirmed the same histological nature as the coxo-pelvic tumor. The patient was subsequently referred to the oncology department for adjuvant chemotherapy and further management. The evolution was marked by a multifocal cardiac and pulmonary recurrence, 10 months after surgical excision. The patient died 5 months later.

Conclusions: Most malignant tumors can metastasize to the heart. In cancer patients, a transthoracic echocardiogram should be performed in the presence of any cardiac warning sign, including dyspnea, chest pain, or a new heart murmur, in order to diagnose any cardiac metastasis that may worsen the patient's prognosis and contribute to the mechanism of death.