Endogenous Lipoid Pneumonia in Adult Autoinflammatory Disease

We describe one of the first cases of endogenous lipoid pneumonia (ELP) in an adult patient with the clinical picture of adult-onset Still disease (AOSD) and a low penetrance genetic background of tumor necrosis factor receptor-associated periodic syndrome (TRAPS). This case highlights the complex pathophysiology of lung involvement in autoinflammatory diseases, operating at the interface of the innate and adaptive immune system. This case presents a 53-year-old immunocompromised woman with treatment refractory autoinflammatory disease and history of macrophage activation syndrome (MAS), presenting to the emergency room with progressive dyspnea and fever. Upon evaluation, chest computed tomography showed diffuse lung disease. Extensive workup, including bronchoscopy with bronchoalveolar lavage, remained negative. Lung biopsy revealed an ELP with intra-alveolar accumulation of cholesterol crystals and foamy macrophages. In the years preceding the event, her autoinflammatory disease had shown to be refractory to both conventional systemic disease-modifying antirheumatic drugs and biologic treatments including tocilizumab, anakinra, and canakinumab. Because of new onset respiratory failure in the context of uncontrolled inflammation, after exclusion of infectious origin, pulse doses of systemic glucocorticoids were administered before induction with cyclophosphamide, followed by maintenance therapy with tacrolimus. Upon treatment, our patient recovered but retained severe interstitial lung disease. Only one case of ELP in adult autoinflammatory disease has been depicted in a patient diagnosed with AOSD, although the entity is more recognized in pediatric literature on systemic onset juvenile idiopathic arthritis (soJIA).