An 82-year-old woman presented with dyspnea on exertion and weight gain of 5 kg over the past month. Her medical history included atrial fibrillation and lung adenocarcinoma (a lung lobectomy was performed 8 years ago). Her blood pressure was 112/60 mm Hg, her heart rate was 100 beats per minute, her respiratory rate was 37 breaths per minute, her body temperature was 36.6°C, and her oxygen saturation was 100% while breathing 10 L of oxygen. A cardiac examination was clinically significant for an irregular rhythm, an increased pulmonic closure sound, and jugular venous distension. Bibasilar coarse crackles and pretibial edema were also noted. A complete blood count had results within normal limits. The serum lactate dehydrogenase level was 278 U/L (to convert to microkatal per liter, multiply by 0.0167). A chest radiographic image showed bibasilar infiltrates. An electrocardiogram was notable for atrial fibrillation, and echocardiography revealed normal left ventricular function, mild right atrial and ventricular dilatation, and severe tricuspid regurgitation (transtricuspid pressure gradient, 40 mm Hg). A contrast-enhanced computed tomography image revealed bilateral ground-glass opacities and right basilar consolidations, with no evidence of thromboembolisms (Figure, A). Para-aortic and inguinal lymphadenopathies were also noted. Presumptive diagnoses of pulmonary hypertension (PH) and right-sided heart failure were made. The patient began receiving dobutamine and furosemide, but she continuously required 2 to 10 L of oxygen, and further invasive evaluations could not be performed. An echocardiogram identified aggravating PH (transtricuspid pressure gradient, 57 mm Hg). A thorough physical examination identified scaly, crusty genital skin lesions pathologically compatible with extramammary Paget disease. The patient deteriorated and died despite treatment. An autopsy was performed (Figure, B).