PNEUMONIA MASQUERADING AS ANTI-SYNTHETASE SYNDROME

Abstract

TOPIC: Lung Pathology TYPE: Fellow Case Reports INTRODUCTION: Anti-synthetase syndrome (ASS) is a rare autoimmune disorder, characterized by anti-aminoacyl transfer RNA synthetase antibodies along with clinical features that can include interstitial lung disease, myositis, Raynaud's phenomenon, non-erosive arthritis, unexplained fever, and/or mechanic's hands. [1] Most patients with ASS with lung involvement present with chronic lung changes, we are describing a case of atypical presentation of ASS lung disease with organizing pneumonia. CASE PRESENTATION: A 60-year-old woman with a history of obstructive sleep apnea, asthma/COPD, and hypothyroidism presented with progressive shortness of breath. The patient had two recent hospitalizations for asthma exacerbation and pneumonia. Chest CT showed patchy scattered ground-glass opacities and consolidative changes with mild traction bronchiectasis changes. Autoimmune workup was positive for anti-SSA (mildly) and ANA but negative for RF, anti-smith, RNP, SSB, SCL70, centromere, PR3, MPO, RNA-Pol 3, and CCP antibodies. Myositis panel was positive for PL-12 Ab. Lung biopsy was consistent with a predominant pattern of organizing pneumonia. In the absence of myositis, the patient was diagnosed with ASS. The patient was initiated on mycophenolic acid and prednisone therapy. Initial pulmonary function tests showed FEV1/FVC is 74, FEV1 is 1.33L (61% of predicted) and FVC is 1.79L (66% of predicted), following treatment repeat PFTs in 3 months showed FEV1/FVC is 68, FEV1 is 1.45L (65% of predicted) and FVC is 2.13L (76% of predicted). Her exercise capacity improved with a six-minute walk test showing a walk distance of 177m with 3 L oxygen before treatment which improved to 435 m with 1 L oxygen post-treatment after 3 months. DISCUSSION: ASS is a group of inflammatory myopathies that requires evidence of anti-aminoacyl transfer RNA synthetase autoantibody and one or more of the following: mechanic's hands, Raynaud's phenomenon, myositis, ILD, arthritis, and/or unexplained fever. [2] Most cases are either misdiagnosed as idiopathic ILD or inflammatory myopathy. CONCLUSIONS: We presented a case of ASS with biopsy-proven organizing pneumonia. Organizing pneumonia is a very rare presentation of ASS and should be kept in mind while evaluating patients with ASS. REFERENCE #1: 1. Stone KB, Oddis CV, Fertig N, Katsumata Y, Lucas M, Vogt M, Domsic R, Ascherman DP. Anti–Jo-1 antibody levels correlate with disease activity in idiopathic inflammatory myopathy. Arthritis & Rheumatism. 2007; 56:3125–3131. [PubMed: 17763431] REFERENCE #2: 2. References Connors GR, Christopher-Stine L, Oddis CV, Danoff SK. Interstitial lung disease associated with the idiopathic inflammatory myopathies: What progress has been made in the past 35 years? Chest. 2010; 138:1464–1474. [PubMed: 21138882] DISCLOSURES: No relevant relationships by Bharat Bhandari, source=Web Response No relevant relationships by Rahat Hussain, source=Web Response No relevant relationships by Soma Sundara Shravan Jyothula, source=Web Response