We present the case of a 50-year-old woman with stage IV invasive ER+/PR-/HER2-ductal breast carcinoma who was admitted to the intensive care unit (ICU) with obstructive shock and hypoxic respiratory failure due to pulmonary tumor thrombotic microangiopathy (PTTM), which significantly improved with chemotherapy. Upon presentation, her heart rate was 145 beats/min, her blood pressure was 86/47 mmHg, her respiratory rate was 25 breaths/min, and her oxygen saturation was 80% in room air. She underwent a broad non-diagnostic infectious evaluation, received fluid resuscitation, and was placed on broad-spectrum antibiotics. Transthoracic echocardiography showed evidence of severe pulmonary hypertension with a pulmonary arterial systolic pressure (PASP) of 77 mmHg. She initially required oxygen via a high-flow nasal cannula (HFNC) at 40 liters/minute and 80% FiO2 and was subsequently placed on inhaled nitric oxide (iNO) at 40 parts per million (PPM) as well as norepinephrine and vasopressin drips for acute decompensated right heart failure. Despite her poor performance status, she was started on chemotherapy with carboplatin and gemcitabine. Over the ensuing week, she was weaned off supplemental oxygen, vasoactive agents, and iNO and discharged home. Repeat echocardiography performed 10 days after the initiation of chemotherapy demonstrated marked improvement in her pulmonary hypertension with a PASP of 34 mmHg. This case highlights the potential role of chemotherapy in altering the course of PTTM in select patients with metastatic breast cancer.