ERBB2 and pulmonary arterial hypertension: While left ventricular dysfunction is a well-documented adverse effect, pulmonary hypertension, pulmonary arterial hypertension (PAH), and right heart failure are rarely reported.<h4>Case presentation</h4>We report the case of a 53-year-old woman with Stage IV HER2-positive invasive ductal carcinoma and well-controlled HIV who presented with shortness of breath, edema, and weakness.