SESSION TITLE: Monday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM INTRODUCTION: Mycobacterium Avium Complex (MAC) infection usually presents as a fibrocavitory or an endobronchial lesion; MAC infection related Immune reconstitution inflammatory syndrome (IRIS) commonly manifests as localized lymphadenitis or endobronchial mass lesions. We present an unusual presentation of MAC related IRIS in an asymptomatic patient. CASE PRESENTATION: 54 year old African American female with past medical history of acquired immunodeficiency syndrome (AIDS) with a CD4 count of 10 cells/uL on antiretroviral therapy (ART) started 2 months ago presented to our hospital with generalized weakness and lightheadedness. A routine chest X ray showed multiple diffuse patchy nodular infiltrates which prompted a chest CT chest revealing multiple patchy nodular densities throughout both lungs with the largest being a cavitating 13 mm lesion in the right upper lobe which raised suspicion for cavitary pneumonia vs tuberculosis. When prompted, she admitted to occasional non-productive cough. Her vitals were a heart rate of 76 bpm, blood pressure of 111/74, respiratory rate of 16, temperature of 96.1F and a saturation of 100% on room air. Physical exam was unremarkable. DISCUSSION: She was started on empiric broad spectrum antibiotics and 3 sputum samples were sent for acid fast bacilli (AFB) staining which revealed negative results. Her initial labs were within normal limits. None of the pulmonary nodules were accessible for interventional radiology-guided biopsy and hence cardio-thoracic surgery performed a right upper lobe wedge biopsy through right video-assisted thoracoscopic surgery, mini-thoracotomy along with chest tube placement. She was then transferred to the ICU briefly for post-operative recovery. Repeat CD4 count was 93 cells/uL. Her viral load was 82 copies/(units) with an unknown pre-treatment viral count. Her sputum samples in the meantime grew MAC in all 3 samples that were initially collected. She was discharged home on azithromycin, ethambutol, and rifabutin to be taken along with her ART but was lost to follow up. CONCLUSIONS: Multiple pulmonary nodules are rarely seen in MAC/ MAC related IRIS infections. Our patient was admitted to the hospital based on the chest X ray findings and showed no clinical signs of infection. CD4 counts improved with ART which likely triggered MAC IRIS as confirmed on all 3 sputum cultures. Reference #1: Riddell J, Kaul DR, Karakousis PC, Gallant JE, Mitty J, Kazanjian PH. Mycobacterium avium complex immune reconstitution inflammatory syndrome: Long term outcomes. J Transl Med. 2007;5:50. https://doi.org/10.1186/1479-5876-5-50 Reference #2: Calligaro G, Meintjes G, Mendelson M. Pulmonary manifestations of the immune reconstitution inflammatory syndrome. Curr Opin Pulm Med. 2011;17(3):180-188. https://doi.org/10.1097/MCP.0b013e328344f692 DISCLOSURES: No relevant relationships by Reshma Golamari, source=Web Response No relevant relationships by shalini ratnagiri, source=Web Response