SESSION TITLE: Medical Student/Resident Diffuse Lung Disease SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Systemic Lupus Erythematosus (SLE) affects lungs (30-50%) with pleurisy being the commonest manifestation. Interstitial Pneumonia (IP) related to SLE was found be less reported about 10% and Organizing Pneumonia (OP) type of IP was noted to be very rare (1). Here, we present a rare case of Organizing pneumonia manifesting in SLE CASE PRESENTATION: A 30-year-old female with history of left breast carcinoma status post bilateral mastectomy, adjuvant chemotherapy and radiation therapy completed in March 2019, sickle cell trait and SLE, first presented in January 2020 with dyspnea and cough. CT chest revealed bilateral lower lobe predominant consolidative opacities with air bronchogram and multifocal sub-pleural ground glass opacities throughout both the lungs [Fig 1A], she was treated for pneumonia. On next admission, she also complained of generalized myalgias/arthralgias and unresolving skin rashes on extremities and neck with topical steroids. No other system involvement except for proteinuria. ANA, ds-DNA and lupus anticoagulant were positive with elevated CRP. CT chest slightly worsened compared to previous CT [Fig 1B]. Bronchoscopy revealed normal gross appearance. RLL trans-bronchial biopsy pathology showed mild chronic interstitial inflammation, intra-alveolar macrophages and focal secondary organizing pneumonia with no specific features. She was started on Plaquenil and long-term low dose steroids that controlled her symptoms DISCUSSION: SLE commonly manifests as lung pathology varying from pleurisy (50%), lung parenchymal disease (10-15%) and pulmonary vascular hypertension (1,2). SLE induced IP commonly presents as Chronic IP (63.6%). The most common HRCT finding is unclassifiable and Nonspecific IP (NSIP) is shown to be the most common histopathology (1). Previous articles reported that pulmonary manifestations especially ILD and serositis usually present as a late manifestation or in SLE patients diagnosed at an older age (1,3,4) with no gender predominance. OP has a well-known association with connective tissue disorders like Rheumatoid Arthritis and Myositis but there are only a handful of cases of SLE reported in association with Bronchio-Obliterans Organizing Pneumonia (BOOP), and commonly seen in older women(1). In contrast our patient was young 30-year-old female who had isolated Organizing pneumonia identified as an early manifestation / initial presentation of SLE. Also, it is possible that OP resulted following a predisposing pulmonary insult in SLE – pneumonia and chest radiotherapy. It was noted from metanalysis that NSIP with OP was a favorable prognosis in patients with SLE compared to other histopathology (2,5) CONCLUSIONS: Though rare, Organizing Pneumonia can occur at any age of onset/ duration of SLE and early diagnosis and treatment with steroids and immunosuppression decreases morbidity and mortality from lung manifestations in SLE, given its favorable prognosis Reference #1: 1. Toyoda Y, Koyama K, Kawano H, Nishimura H, Kagawa K, Morizumi S, et al. Clinical features of interstitial pneumonia associated with systemic lupus erythematosus. Respir Investig. 2019;57(5):435–43. Reference #2: 2. Enomoto N, Egashira R, Tabata K, Hashisako M, Kitani M, Waseda Y, et al. Analysis of systemic lupus erythematosus-related interstitial pneumonia: a retrospective multicentre study. Sci Rep. 2019;9(1):1–11.v Reference #3: 5. Tselios K, Urowitz MB. Cardiovascular and Pulmonary Manifestations of Systemic Lupus Erythematosus. Curr Rheumatol Rev. 2017;13(3):206–18. DISCLOSURES: No relevant relationships by Rathnavali Katragadda, source=Web Response No relevant relationships by Vinod Khatri, source=Web Response No relevant relationships by Leela Krishna Vamsee Miriyala, source=Web Response No relevant relationships by Shanti Pittampalli, source=Web Response