[Rheumatoid arthritis diagnosis based on the detection of a pulmonary rheumatoid nodule in a patient with Hansen's disease].

A 77-year-old man with Hansen's disease was referred to our hospital because of a small nodular lesion detected adjacent to the pleura in the right lower lobe (S10) on chest CT. He had lost all ten fingers due to Hansen's disease and was using a prosthetic limb after amputation of the right lower leg. Although the patient had an 11-year history of shoulder and back pain and was suspected of having interstitial pneumonia 6 years previously, no detailed examination had been conducted. Bronchoscopy did not yield a definitive diagnosis, and a lung biopsy was performed under thoracoscopic guidance. Histological examination of the resected nodule with colliquative necrosis revealed palisading granulomas with multinucleated giant cells and plasma cell infiltration with formation of lymphoid follicles. Since serum levels of both anti-MMP3 and anti CCP antibodies were elevated, rheumatoid arthritis (RA) with rheumatoid lung was diagnosed. Therefore, the nodule was considered a rheumatoid nodule. Since diagnosis of rheumatoid arthritis is difficult when lacking characteristic joint manifestations, it is important to include rheumatoid nodules as a differential diagnosis and to measure RA specific autoantibodies, to make a comprehensive diagnosis for non-specific necrotizing granulomas.