Late onset of hypoxemia due to a pulmonary arteriovenous malformation during selective estrogen receptor modulator therapy.

A76-year-old woman with unexplained hypoxemia and severe exertional dyspnea was admitted to our department. The symptoms had appeared during tamoxifen therapy after resection of breast carcinoma; history revealed recurrent upper gastrointestinal bleeding, epistaxis, and a granddaughter deceased because of a cerebral arteriovenous malformation. Chest computed tomography scan showed the presence of a highly vascularized nodule in the right lower lobe. Right pulmonary artery angiography demonstrated a large pulmonary arteriovenous malformation (PAVM) (Online Video 1) with massive right-to-left shunt (A, B, C; Online Video 2); this confirmed the diagnosis of hereditary hemorrhagic telangiectasia (1). The arrows point to the right upper pulmonary vein. We decided to percutaneously close the PAVM. An occlusion test was performed before the procedure (D); O2 saturation rose from 87% to 96%. The PAVM was subsequently closed using a vascular occlusion device (E) with complete abolishment of the right-to-left shunt (F; Online Video 3). It is likely that selective estrogen receptor modulator therapy may have been responsible for the enlargement of the PAVM in our patient (2).