B57-08 Artificial Stone Silicosis and Antisynthetase Syndrome: A Rare Association

Abstract Background Artificial stone fabrication involves exposure to high concentrations of respirable crystalline silica (RCS), leading to rapidly progressive silicosis in relatively young workers. Beyond pulmonary fibrosis, silica exposure has also been linked to autoimmune diseases. Proposed mechanisms include macrophage activation via the NLRP3 inflammasome and oxidative stress-induced epithelial barrier dysfunction. While strong associations have been established with systemic sclerosis and rheumatoid arthritis, the link between artificial stone exposure and antisynthetase syndrome remains poorly defined. Case Presentation A 55-year-old non-smoker, employed for 15 years in an artificial stone manufacturing plant with significant silica exposure, presented with one month of progressive dyspnea, muscle pain, and weakness.Chest CT angiography excluded pulmonary embolism but showed findings compatible with silicosis—mild mediastinal and hilar lymphadenopathy without calcifications and micronodular opacities predominantly in the upper lobes. Pulmonary function testing revealed mild restriction and moderate diffusion impairment (FEV1 79%, FVC 76%, FEV1/FVC 0.83, DLCO 52%).EBUS-guided lymph node cryobiopsy demonstrated no malignancy or granulomas and no birefringent particles under polarized light. Laboratory testing revealed elevated CPK (6000 IU/L) and proximal muscle weakness. Muscle biopsy of the left rectus femoris showed immune-mediated inflammatory myopathy. MRI of pelvic and thigh muscles revealed diffuse edema and gadolinium enhancement. Autoimmune serology was positive for Anti-Jo1 and Anti-MDA5 antibodies, confirming antisynthetase syndrome associated with silicosis. Management and Outcome High-dose prednisone (80 mg/day) and azathioprine were initiated. Due to limited response, therapy was escalated to mycophenolate mofetil (MMF), rituximab, and subsequently intravenous immunoglobulin (IVIG). The patient experienced improvement in myalgia but persistent weakness. Lung function improved by 20% (740 mL increase in vital capacity) without change in diffusion capacity and no evidence of disease progression on imaging while maintained on prednisone 15 mg/day. Conclusion This case illustrates the rare coexistence of silicosis and antisynthetase syndrome, supporting a potential role of silica exposure in triggering immune-mediated myopathies. Silicosis should be considered as a specific interstitial lung disease (ILD) within the antisynthetase syndrome spectrum. This abstract is funded by: None