SESSION TITLE: Monday Fellow Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM INTRODUCTION: With the evolution of diagnostic and treatment modalities for venous thrombo-embolic disease we have seen a significant reduction in the case fatality rate as well as a steady increase in the total number of cases diagnosed worldwide. While pulmonary infarction is an uncommon complication of PE, it's further evolution to cavitaty formation is exceedingly rare and we would like to present and discuss such a case. CASE PRESENTATION: Our case is that of a 68 year old gentleman with a known history of severe obstructive lung disease and HIV who initially presented to the hospital with complaints of acute severe dyspnea. He was diagnosed with a pneumothorax, and after successful chest tube placement a non contrast computer tomography (CT) scan of his chest showed a cavitary lesion in the superior segment of the right lower lobe. Subsequent testing also revealed an acinetobacter baumanii infection for which he was treated with a prolonged course of antibiotics. Three months after the initial admission, he returned to the hospital with dyspnea at which time a CT of his chest with contrast showed extensive bilateral PE with radiological signs of chronicity and a new left lower lobe infiltrate with cavitation. The distribution of his chronic PE was consistent with both his previously noted right lung and current left lung cavities. During his second hospitalization, no causative organisms could be isolated however he was treated empirically with antibiotics. His PE was treated with anticoagulation and he was successfully followed in the outpatient setting with serial CT imaging which showed resolution of both cavitary lesions and no new PE's on subsequent CT scans. DISCUSSION: The dual blood supply to the lungs make pulmonary infarction an uncommon sequela of PE. Less than 1% of PE's have been noted to lead to cavitation after infarction. While multiple risk factors have been noted for cavitation after a PE, including old age, chronic lung disease, a history of heart failure and the size of the infarct area, the average time to cavitation is 2-3 weeks. Areas of infarct are usually aseptic however secondary infections can lead to hastening of the formation of a cavitary lesion. Our patient presented to the hospital with a formed cavity implying that he had suffered from the initial PE a few weeks before. While cavity formation after pulmonary infarcts has been well described in the literature, our case is unique because of the presentation as well as because he developed multiple cavitations at different times over the course of treatment which is an extremely unusual and rare clinical course for a PE and has not been previously noted in the literature. CONCLUSIONS: While cavitary lesions are a rare complication of pulmonary infarcts, PE must always be considered as part of the differential diagnosis. Early appropriate treatment can prevent complications that have been noted with acute and chronic PE. Reference #1: Sonmez, M., Aboussouan, L. S., Farver, C. A. R. O. L., Murthy, S. C., & Kaw, R. (2018). Pulmonary infarction due to pulmonary embolism. Reference #2: Konstantinides, Stavros V., et al. "Management of pulmonary embolism: an update.” Journal of the American College of Cardiology 67.8 (2016): 976-990. Reference #3: Koroscil, Matthew T., and Timothy R. Hauser. "Acute pulmonary embolism leading to cavitation and large pulmonary abscess: a rare complication of pulmonary infarction.” Respiratory medicine case reports 20 (2017): 72-74. DISCLOSURES: No relevant relationships by Taaran Cariappa Ballachanda Subbaiah, source=Web Response No relevant relationships by Jason George, source=Web Response