Clinicopathologic features of rheumatoid nodules: a retrospective analysis

Objectives The clinical and histopathologic features of patients that have been diagnosed with rheumatoid nodules were investigated. Methods This study included patients with rheumatoid nodules, confirmed by histologic assessment, between 2005 and 2018 at the Hanyang University Hospital. Each patient had a total score of 6 or more according to the American College of Rheumatology criteria. Results A total of 57 cases were included in this study. The median age of the patients at the time of diagnosis was 57 years (range, 39–70 years). The average duration between the onset of treatment and occurrence of rheumatoid nodule was 11.6 years. Bone erosion was observed in 44 patients (77.2%). Among 57 patients, 56 (98.2%) were treated with disease-modifying anti-rheumatic drugs; most of the patients (87.7%) showed high-positive rheumatoid factor or high-positive anti-citrullinated protein antibodies. The foot, hand, and wrist, in order of decreasing frequencies, were the anatomical sites with the highest occurrence of rheumatoid nodules, whereas, the soft tissue adjacent to the joint, subcutis, dermis, lung parenchyma, and submucosal layer of the supraglottic area, also in an order of highest frequency, were the histological sites with the highest occurrence. Microscopically, central necrobiosis was present in all cases. Stromal fibrosis (96.5%), palisading of histiocytes (82.5%), perivascular lymphocytic infiltration (68.4%), and cleft or cystic degeneration (63.2%) were also observed. Conclusions A clinicopathological review of cases diagnosed with rheumatoid nodules histologically was performed to confirm characteristics that can help clinicians understand the pathophysiology of the condition and make accurate diagnoses of rheumatoid nodules. Key Points • We reviewed the clinical, imaging, and histologic features of rheumatoid nodule. • The average duration between the onset of treatment and occurrence of rheumatoid nodule was 11.6 years. • Among 57 rheumatoid nodule patients, 98.2% were treated with disease-modifying anti-rheumatic drugs.