What are rheumatoid nodules?

Answer 1

A rheumatoid nodule is a firm feeling swelling or lump which occurs within 2 years in about 5% of people once they are diagnosed with rheumatoid arthritis. And about 25% of RA victims wil get them at some time during their lives. It is very unusual for 'rheumatoid nodules to appear if not accompanied with Arthritis. They are usually subcutaneous ( under the skin) especially over bony prominences such as the tip of the elbow or over the knuckles. they can also appear in the lining of the lungs as well as other organs. Sizes of Nodules vary from that of about a pea to that of a small orange. Quite often they are associated with synovial pockets or bursae. Generally rheumatoid nodules are not painful or in any way disabling, Unless they are on a place where there is a lot of contact such as on the back of the arm under the elbow where people tend to rest their arms when doing desk work an similar situations. Other then that they are just not very attractive. In isolated cases they can appear on parts of the body such as the upper eyelid, distal region of soles, vulva and internally in the gallbladder, lung, heart valves, larynx and spine.

Rheumatoid nodules consist of a shell of fibrous tissue surrounding a centre of fibrinoid necrosis. Pea sized nodules have one centre. Larger nodules tend to be multilocular, with many separate shells or with connections between the necrotic centres. Individual necrotic centres may contain a cleft or several centres of necrosis may all open on to a large bursal pocket containing synovial fluid. The boundary between the necrotic centre and the outer fibrous shell is made up of the characteristic feature of the nodule, which is known as a cellular palisade. The palisade is a densely packed layer of macrophages and fibroblasts which tend to be arranged radially, like the seeds of a kiwi fruit or fig. Further out into the fibrous shell there is a zone that contains T lymphocytes and plasma cells in association with blood vessels. The overall histological picture is essentially identical to that of rheumatoid synovitis with the main differences being that the palisade replaces the synovial intima (they may blend imperceptibly in bursae) and an almost total absence of B lymphocytes.(Sourced from Wikipedia)