Pulmonary Involvement Successfully Treated With Infliximab in a Patient With Pyoderma Gangrenosum and Rheumatoid Arthritis: A Case Report

Pulmonary involvement of pyoderma gangrenosum (PG) is rare and has been observed in few patients with rheumatoid arthritis (RA). We describe the case of a 72‐year‐old woman with RA who simultaneously developed multiple cavitary pulmonary nodules and worsening cutaneous PG. Differential diagnoses included PG‐related pulmonary lesions and rheumatoid nodules, which may cavitate and are difficult to distinguish radiologically and histologically. Bronchoscopy and video‐assisted thoracoscopic surgery were performed. A histopathological evaluation revealed nonspecific findings, and infection was considered unlikely. Infliximab (IFX) was initiated because limited reports have suggested its potential benefit for pulmonary PG and potential usefulness for lesions that represent rheumatoid nodules. To the best of our knowledge, this is the first report of pulmonary involvement in a patient with PG and RA that was successfully treated with IFX. This case highlights diagnostic challenges and suggests that tumour necrosis factor‐α inhibitors may be a promising therapeutic option for select cases.