Cavitary Pulmonary Nodules Associated With Leflunomide Therapy in Rheumatoid Arthritis: A Case Report and Literature Review.

Rheumatoid arthritis (RA) may present with extra-articular pulmonary manifestations, including rheumatoid lung nodules. Leflunomide is an effective disease-modifying antirheumatic drug, but increasing case reports suggest an association with accelerated pulmonary nodulosis. We describe a 61-year-old woman with long-standing seropositive RA who developed left-sided lower chest pain, generalized weakness, fatigue, and loss of appetite after switching from methotrexate to leflunomide 20 mg/day. CT imaging demonstrated multiple bilateral cavitary nodules predominantly in the lower lobes. Extensive evaluation (bronchoscopy with microbiology, QuantiFERON-TB Gold, and malignancy assessment) was negative, and video-assisted thoracoscopic surgery lung biopsy showed necrotizing granulomatous inflammation consistent with rheumatoid nodules. The leflunomide dose was initially reduced and then discontinued, and methotrexate was reintroduced; at the four-month follow-up, the patient was clinically well without synovitis, and a CT eight months later showed near-complete regression of prior nodules, with residual left basal fibrotic changes containing calcifications and a remaining non-cavitary right lower-lobe nodule. Clinicians should consider leflunomide-associated pulmonary nodulosis in RA patients with new cavitary nodules after excluding infectious and malignant etiologies, and discontinuation of the drug may lead to radiologic improvement.