A Rare Case of Necrotizing Myopathy and Fibrinous and Organizing Pneumonia with Anti-EJ Antisynthetase Syndrome and SSA Antibodies

Abstract

BACKGROUND Idiopathic inflammatory myopathies are autoimmune disorders that can involve the skin, joints, muscles, and lungs. The most common of these disorders are dermatomyositis, polymyositis, overlap syndrome, and inclusion body myositis. Necrotizing autoimmune myopathy is an idiopathic inflammatory myopathy that is rarely associated with Sjögren's syndrome. The most common lung findings associated with anti-EJ antisynthetase syndrome are nonspecific interstitial pneumonia and usual interstitial pneumonia; this condition is rarely associated with fibrinous and organizing pneumonia. CASE REPORT Here, we present a rare case of necrotizing myopathy and fibrinous and organizing pneumonia in a 34-year-old African American man with Sjögren's syndrome and anti-EJ antibodies. The patient's presenting symptoms were cough and proximal muscle weakness of the extremities. He had elevated serum creatine kinase level, aldolase level, and erythrocyte sedimentation rate. Myositis panel was positive for anti-EJ antibodies. Chest radiography was consistent with bilateral interstitial infiltrates. CT chest showed patchy bilateral infiltrates. Quadriceps muscle biopsy revealed widespread necrotic fibers and lung biopsy showed fibrinous and organizing pneumonia. The patient responded well to immunoglobulin therapy, mycophenolate, and prednisone, which resulted in complete resolution of bilateral infiltrates and improved muscle pain and weakness. CONCLUSIONS Myopathies are characterized by myalgia and muscle weakness due to muscle fiber dysfunction and are associated with autoimmune diseases. Histopathological features may differ in idiopathic inflammatory myopathies. It is important to recognize the rare association of anti-EJ autoantibodies with necrotizing myopathy and interstitial lung disease, which responds well to methylprednisolone and intravenous immunoglobulin.

Figure 1.

(A) Chest radiograph shows patchy areas of consolidation in the left lower lobe. (B) Chest radiograph shows complete resolution of the pulmonary infiltrates at the 1-month follow-up visit.

Figure 2.

(A) Left quadriceps muscle biopsy revealed widespread necrotic fibers and regeneration but no mononuclear inflammatory cell infiltrate. (B) CD68 stain revealed scattered necrotic muscle fibers invaded by phagocytes.

Figure 3.

(A) Chest CT axial view shows patchy areas of consolidation, predominantly in lower lobes. (B) Chest CT axial view shows complete resolution of consolidation at the 1-month follow-up visit.

Figure 4.

(A) Lung biopsy revealed acute organizing pneumonia with fibroblastic proliferation filling airspaces and a mild lymphocytic infiltrate. (B) Lung biopsy reveled fibroblastic proliferation within an alveolar space and mildly thickened alveolar septa.