A 39-year-old woman with a history of Stage IA breast cancer (ER weakly positive, PR negative, HER-2 negative) treated with bilateral nipple-sparing mastectomies 3 years prior, presented to the emergency department with 3 weeks of progressive dyspnea on exertion. Pulse was 108 and oxygen saturation (SpO2) on room air was 91% and 84% with ambulation requiring up to 3 L of supplemental oxygen via nasal canula. Physical exam was notable for a decrease in SpO2 while sitting upright which improved with lying in the supine position. Laboratory values were notable for platelet count of 89,000 K, calcium 11.2 mg/dL, alkaline phosphatase 627 U/L, aspartate aminotransferase 148 U/L, and alanine aminotransferase 143 U/L. Computed tomography of the chest with intravenous contrast pulmonary embolism protocol was negative for pulmonary embolism, but revealed numerous hepatic lesions and numerous sclerotic osseous lesions. Transthoracic echocardiogram (TTE) with saline contrast and bubble study revealed lack of bubbles in the left ventricle after cough and the presence of bubbles after 7 heartbeats, suggestive of a transpulmonary shunt (as shown in Fig. 1, 2). The patient underwent an ultrasound-guided biopsy of a liver lesion and was diagnosed with metastatic breast cancer (ER weakly positive, PR negative, HER-2 negative). She was started on chemotherapy with weekly paclitaxel at a dose of 60 mg/m2. After completion of a 3-week cycle of treatment, her hypoxia and supplemental oxygen needs resolved, and she had a significant reduction in her transaminases (as shown in Table 1).