Primary undifferentiated spindle cell sarcoma obstructing the right ventricular outflow tract

BACKGROUND: Primary undifferentiated spindle cell sarcoma in the right ventricle is an extremely rare tumor. Radical surgical excision is the optimal treatment for long-term survival due to poor response to chemotherapy or radiotherapy at an advanced stage. CASE PRESENTATION: A 42-year-old man with no previous medical history presented with mild dyspnea on exertion and abdominal distension that lasted a week. Computed tomography (CT) revealed a huge homogeneous mass completely obstructing the right ventricle and extending into the pulmonary trunk. However, he suddenly collapsed the next day while on his way to an echocardiography. An extracorporeal membrane oxygenation (ECMO) device was inserted percutaneously and ECMO support was urgently initiated. Based on consideration of right ventricular outflow tract (RVOT) obstruction in the initial CT scan, we decided to remove the mass from the right ventricle immediately. The main mass was resected to relieve the RVOT obstruction, and after the operation, the ECMO was removed from the operation room. However, the patient failed to regain consciousness and electroencephalography (EEG) and subsequent magnetic resonance imaging (MRI) indicated severe hypoxic brain damage. We assume CPR was unsuccessful because the mass completely blocked the RVOT. Pathology revealed the mass was an undifferentiated spindle cell sarcoma. CONCLUSIONS: We present the case of a 42-year-old male with cardiac arrest due to right ventricular outflow tract obstruction by a tumor of the right ventricle. Surgical resection was performed and in histopathology it was proved to be an undifferentiated spindle cell sarcoma.