Pulmonary Tumor Embolism Microangiopathy: A Cause of Respiratory Failure in Advanced Malignancy

INTRODUCTION: Etiologies of acute respiratory failure in breast cancer patients are diverse (acute respiratory distress syndrome, acute interstitial pneumonia, pulmonary fibrosis, radiation pneumonitis, malignant infiltration). Pulmonary tumor embolism microangiopathy (PTEM) is a rare complication of advanced cancer that often presents as respiratory failure, pulmonary hypertension, right heart failure, and sudden death. Breast cancer is the most common primary cause of PTEM. It takes an aggressive course and presents with a challenge to diagnose and eventually manage. Here, we present the case of PTEM in a woman with advanced breast cancer. CASE SUMMARY: A 53-year-old female presented to the emergency department with shortness of breath. Her past medical history was significant for HER-2 positive breast cancer with metastatic lesions in the brain, spine, and liver. In the emergency department (ED), the patient was tachycardic, tachypneic, hypoxic, hypotensive and hyperthermic. Laboratory results showed anemia, severe thrombocytopenia, alkalemia, hypoxia with decreased levels of arterial oxygen tension, decreased arterial carbon dioxide with a compensatory metabolic acidosis as well as grossly elevated transaminases, elevated D-Dimer, and multiple inflammatory markers. CT angiography and echocardiogram were performed but they failed to establish a definite diagnosis. The patient was admitted to the intensive care unit due to progressive acute hypoxic respiratory failure despite being tested negative for pulmonary embolism. Despite resuscitative measures with intravenous diuretics, multiple transfusions as well as antibiotics, she remained tachypneic with respiratory rate of 40/min and oxygen saturation between 70-80 percent. She passed away a few hours later. No autopsy was performed. CONCLUSION: We recommend that if a patient with established malignancy presents with deteriorating lung function whereby there is evidence of progressive dyspnea and consolidation on radiographs, empirical antimicrobial treatment has failed to show improvement and thromboembolism has been ruled out, PTEM should be considered for early diagnosis.