fibroblastic rheumatism
Fibroblastic rheumatism can resemble MRH. It is a rare fibroblastic (not histiocytic) disease with at least 33% of cases occurring in children. Patients develop the rapid onset of symmetric polyarthritis, mainly of the upper extremities. DIP joints can be involved. Palmar thickening and inability to extend fingers is seen in 80% of cases, leading to functional disability. Sclerodactyly and skin thickening of the arms and trunk can be seen. Raynaud’s phenomenon occurs in 50% of cases. Cutaneous manifestations start as maculopapular lesions that develop into nodules over the extensor surfaces of the MCP joints and fingers. They usually develop after the arthritis. There is no association with malignancy or autoimmune disease. Serologies are unremarkable. Radiographs can show joint destruction resembling MRH. Nodule and synovial biopsies show “spindle-shaped” fibroblastic cells that are myofibroblasts. Treatment with prednisone, methotrexate, and TNF antagonists has had variable results. Fibroblastic rheumatism may remit spontaneously but usually recurs.
