The term "rheumatoid nodule" refers to a firm, rounded lump under the skin, often found near joints in people with rheumatoid arthritis. Other names for this symptom include subcutaneous nodules, rheumatoid nodules, and rheumatoid arthritis nodules. These nodules are a result of an abnormal immune response, causing inflammation and the accumulation of cells and tissues under the skin. They can vary in size and can be painless or tender. Synonyms for rheumatoid nodule include nodular swelling, rheumatic nodule, and nodular lesions. While they are not dangerous themselves, rheumatoid nodules can be indicative of severe rheumatoid arthritis and may require medical treatment.