TOPIC: Lung Pathology TYPE: Medical Student/Resident Case Reports INTRODUCTION: Unilateral pulmonary artery agenesis (UPAA) is a rare congenital condition with a prevalence of 1 in 200,000 adults3. It is often associated with other cardiovascular abnormalities, and occurs most frequently as an absence of the right branch. Hemoptysis has been reported in up to 10% of patients with UPAA1,2. Here we describe the case of a patient with UPAA and massive hemoptysis after SARS-CoV-2 infection. CASE PRESENTATION: A 27-year-old female with a past medical history significant for patent ductus arteriosus, atrial septal defect, hypoplastic right lung, agenesis of the right pulmonary artery, von Willebrand Disease, and iodinated contrast allergy who presented with complaint of persistent hemoptysis after COVID-19 infection. The patient had been diagnosed with COVID-19 two weeks prior, and was treated as an outpatient without significant symptoms. She subsequently developed acute onset of massive hemoptysis, and upon presentation was admitted to the intensive care unit and intubated for airway protection. The case was discussed with interventional radiology (IR). Given the patient's contrast allergy, bronchoscopy was pursued in an attempt to identify the location of bleeding. Flexible bronchoscopy showed extensive bilateral airway casting with clot as well as active bleeding from the right mainstem bronchus. Significant hypoxia was encountered due to the clot burden. Bronchial artery embolization (BAE) was discussed with IR, but there were concerns for lung necrosis due to embolization in the setting UPAA. Hematology evaluated the patient, and administered Factor VIII/von Willebrand Factor Complex. The patient was evaluated for ECMO in the setting of severe refractory hypoxia. Fortunately, the active bleeding resolved and a 14 cm clot was extracted using alligator forceps via a bronchoscope. The patient's severe hypoxia resolved and she was subsequently extubated. DISCUSSION: Massive hemoptysis is a life-threatening condition. Treatment is centered on identifying the location of the hemorrhage. BAE is often required if the bleeding cannot be managed endoscopically. Our patient presented a unique problem as her bleeding appeared to be coming from the right lung whose vascular supply subsisted from the bronchial artery system alone. There is a paucity of literature on this particular issue, and it is unclear if BAE increases the incidence of ischemia and tissue necrosis. Fortunately this patient avoided the need for BAE and ultimately had a favorable outcome. CONCLUSIONS: This case highlights not only massive hemoptysis in the setting of recent COVID-19 infection, but the difficulties that pulmonary artery agenesis can pose when attempting to provide treatment. REFERENCE #1: Lee EY, Boiselle PM, Cleveland RH. Multidetector CT evaluation of congenital lung anomalies. Radiology. 2008;247(3):632–48 REFERENCE #2: Zylak CJ, Eyler WR, Spizarny DL, Stone CH. Developmental lung anomalies in the adult: radiologic-pathologic correlation. Radiographics. 2002;22 Spec No:S25–43 REFERENCE #3: Reading DW, Oza U. Unilateral absence of a pulmonary artery: a rare disorder with variable presentation. Proc (Bayl Univ Med Cent). 2012;25(2):115-118. DISCLOSURES: No relevant relationships by Arjan Ahluwalia, source=Web Response No relevant relationships by Henry Lam, source=Web Response No relevant relationships by Theresa Maitz, source=Web Response No relevant relationships by Brian Miller, source=Web Response No relevant relationships by Kaitlyn Musco, source=Web Response