Abstract Nonspecific interstitial pneumonia (NSIP) can be readily appreciated on computed tomography radiography (CT) of the chest as part of a full pulmonary workup for patients with anti-synthetase syndrome. A bilateral nonspecific interstitial pneumonia or organizing pneumonia is often seen in these patients 1. Rarely, unilateral NSIP can be seen on imaging and is usually indicative of a secondary underlying cause 2. We present a case in a 75 year old male with unilateral, right-sided NSIP, found to be secondary to an idiopathic inflammatory myopathy from anti-synthetase syndrome in addition to hypersensitivity pneumonitis. The patient’s computed tomography angiography (CTA) with pulmonary vein mapping was reviewed due to the patient’s chief complaint of dyspnea, and unilateral NSIP changes were found to be present on the right lung along with a relatively normal left lung parenchyma. Subsequent antibody testing consisting of an extended myositis antibody panel later confirmed a diagnosis of anti-synthetase syndrome with a positive autoantibody to PL-7. Our patient presented with unilateral NSIP in contrast to more severe, bilateral lung involvement classically seen with anti-synthetase syndrome with positive anti-PL-7 antibodies 2. Furthermore, the patient’s workup was also significant for a positive hypersensitivity pneumonitis panel. He eventually underwent a transbronchial cryo-biopsy of the right lower lobe and right middle lobe with results significant for organizing pneumonia with vague non-necrotizing granulomas and a mild cellular interstitial infiltrate. Expert review of the pathology by Mayo Clinic strongly suggested connective tissue disease-associated interstitial lung disease, amiodarone-induced pulmonary toxicity or hypersensitivity and less likely aspiration pneumonitis. The patient had no aspiration events, esophagram was normal, and all cultures from bronchoscopy were negative. He responded to a prolonged tapered course of systemic glucocorticoids in addition to allergen avoidance and continues to improve in regards to symptoms. Follow up pulmonary function testing revealed no evidence of restrictive disease or impairment in gas exchange. This case highlights a rare unilateral manifestation of interstitial lung disease, likely secondary to anti synthetase syndrome or hypersensitivity pneumonitis, emphasizing the clinical importance of prompt recognition and management of inflammatory myopathies in patients with atypical interstitial patterns of uncertain etiology on chest CT. 1. Marie I, et al. “Clinical Manifestations and Outcome of Anti-PL7 Positive Patients with Antisynthetase Syndrome.” Eur J Intern Med. 2013;24(5):474-9. 2. Kligerman S, et al. “Nonspecific interstitial pneumonia: radiologic, clinical, and pathologic considerations.” RadioGraphics. 2009; 29: 73-87 This abstract is funded by: Eisenhower Health
Silvestre et al. (Fri,) studied this question.