Dramatic Improvement of Pulmonary Tumor Thrombotic Microangiopathy in a Breast Cancer Patient Treated With Bevacizumab

A 47-year-old woman diagnosed with stage IV left-sided breast cancer (T3N3aM1; OSS, HEP, LYM) 6 months back presented with respiratory distress. On admission, she developed respiratory failure, requiring 4 L of oxygen support. Pulmonary embolism was ruled out because computed tomography revealed no obvious pulmonary artery thrombus. Transthoracic echocardiography revealed a significant enlargement of the right ventricle and atrium. Pulmonary hypertension was confirmed via right heart catheterization. Pulmonary artery wedge aspiration cytology revealed adenocarcinoma cells. Based on these findings, we diagnosed the patient with pulmonary tumor thrombotic microangiopathy (PTTM) caused by breast cancer. Immediate chemotherapy (paclitaxel and bevacizumab) for breast cancer and concurrent treatment for pulmonary hypertension and disseminated intravascular coagulation were initiated. We could successfully control her condition with paclitaxel and bevacizumab for a year, and the patient survived for 1 year and 8 months. PTTM is a rare disease characterized by pulmonary hypertension and hypoxemia arising due to tumor embolization of the peripheral pulmonary arteries. PTTM is a rapidly progressing condition with no established treatment guidelines; its pathogenesis involves vascular endothelial growth factor (VEGF). This report highlighted the potential of bevacizumab, known for its anti-VEGF effect, in improving the pathological condition of patients with PTTM caused by breast cancer.