[Rheumatoid arthritis with Castleman-like histopathology in lymph nodes: A case report].

Rheumatoid arthritis (RA) is a common chronic autoimmune inflammatory disease, characterized by persistent polyarthritis. Patients with RA may exhibit varying degrees of B lymphocyte activation, clinically manifested as enlarged lymph nodes. Disease-modifying anti-rheumatic drugs and glucocorticoid are often used to treat RA. Biological agents targeting tumor necrosis factor alpha, interleukin-6(IL-6), and B lymphocytes are often used to treat rheumatoid arthritis. Castleman disease (CD) is a rare benign lymphoproliferative disorder. Histopathological examination is the most important method to diagnose this disease. Based on the different lymph node involvement areas CD can be divided into unicentric CD(UCD) and multicentric CD(MCD). Surgical removal of lymph nodes is a common treatment method for UCD. MCD often requires chemotherapeutic drugs combined with glucocorticoid therapy. For the most recent years, biological agents targeting IL-6 and B lymphocytes have shown good curative effects on CD. In the past, patients with rheumatic immune disease accompanied by Castleman like histopathology in lymph nodes were commonly referred to as rheumatic immune disease combined with CD. In 2021, experts unanimously agreed that autoimmune diseases with Castleman like lymphadenopathy should be diagnosed as rheumatic autoimmune diseases with Castleman like histopathology in lymph nodes. This report introduces a 65-year-old female patient with rheumatoid arthritis who was admitted to the hospital due to joint swelling and pain. Physical and chemical examinations after admission showed that rheumatoid arthritis was in an active phase. Chest CT revealed multiple enlarged lymph nodes in the right armpit. Then it was removed by surgery. The histopathological report showed that the lymphatic sinus disappeared, the lymphoid tissue proliferated, the lymphoid follicles increased, and the size was inconsistent. The small lymphocytes around the germinal centers of some follicles were concentric circles, and the follicular interstitial blood vessels proliferated. She was diagnosed with rheumatoid arthritis with Castleman like histopathology in lymph nodes and was treated with methotrexate and hydroxychloroquine sulfate combined with glucocorticoids. The patient was followed up for 2 years. In the first year after sur-gery, the patient' s condition remained stable and there was no growth of lymph nodes in the right axilla. The patient passed away due to severe infection in the second year after the surgery.