Occasional patients have had paraproteinemia, cold agglutinins, cryoglobulinemia, or hypergammaglobulinemia. Synovial fluid findings are variable, and reports exist of elevated counts of neutrophils or mononuclear cells. Routine radiographs of joints may be helpful. Bilaterally symmetrical, sharply circumscribed erosions spread from the margins to the joint surfaces. Separation often occurs of the bone ends, but no subchondral sclerosis and little or no periosteal reaction are seen.
Osteoporosis is mild or absent.
Erosions in osteoarthritis begin centrally rather than at the joint margins. Erosions with psoriatic arthritis and Reiter disease are asymmetric, with poorly defined margins, and with associated periosteal new bone formation. MRI and CT scanning have been reported to be helpful, but are not needed in most cases. These cells can be huge or bizarre, and may be multinucleated. Varying numbers of lymphocytes or eosinophils may be present.