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Fibroblastic rheumatism (FR) is a rare disorder of unknown cause first described in 1980.1 We here report the first Scandinavian patient with FR.
A 55 year old Danish woman was referred to our department in July 2000 with a 2½ year history of pain in the proximal interphalangeal (PIP) joints, knees, and ankles. The pain worsened over night and upon exercise. On examination, the right knee and the second PIP joint on the left hand were tender and swollen. The other PIP joints and both wrists were tender. On both hands there were several pink, 3–10 mm, tender and mobile skin nodules (fig 1), and a 20 mm nodule under the left foot.
All laboratory investigations were normal, including erythrocyte sedimentation rate, C reactive protein, haemoglobin, white blood cell count, platelets, and differential count. IgM rheumatoid factor, antinuclear antibodies and antineutrophil cytoplasmic antibodies were not found. An x ray examination of the hands demonstrated osteoarthritis of the distal interphalangeal joints.
Two skin nodules were removed and examined by light microscopy (fig 2): they showed areas with densely packed uniform spindle cells surrounded by bundles of thickened collagen fibres and vascular granulation tissue. The biopsy specimens were without inflammatory cells, histiocytes, giant cells, granulomas, or foreign bodies. Special staining did not disclose any elastic fibres. Immunochemical staining of paraffin sections for myofibroblasts was positive for vimentin, but negative for desmin and α-smooth muscle actin.
Treatment with celecoxib and physical therapy was started but had no effect on the symptoms.
On follow up in 2003, the patient had severe, intermittent arthralgia and she was unable to work. She had a nodular thickening of the palmar aponeurosis and a slight contracture of the fingers on both hands. x Ray findings of her hands had not changed.
The diagnosis FR was based on the presence of skin nodules, joint symptoms, histopathological features, a poor outcome, and the absence of another diagnosis that could explain these characteristics. There was no evidence of systemic sclerosis, and the patient did not fulfil classification criteria for rheumatoid arthritis.2 The hallmark of multicentric reticulohistiocytosis is giant cells of a foreign body type and histiocytes in pathological specimens.3 These features were absent in both skin biopsy specimens.
The presenting symptom in FR may be joint symptoms or skin nodules, but the presence of both is pivotal for the diagnosis. A polyarthritis in small joints is often described, but a monarthritis affecting large joints may also be seen. Subcutaneous nodules have been noticed in almost every area of the skin. They are pink or flesh coloured, 2–30 mm, and sometimes surrounded by an erythema. Some patients have a diffuse swelling of the hands, and some develop a thickening of the palmar fascia.
Blood tests are not diagnostic and initial x ray examination of the affected joints is usually normal. Although being non-specific, light microscopy of nodules have shown a consistent pattern in all published cases (table 1). Occasionally, myofibroblasts8 have been verified.
Nearly all patients with FR have been treated with either oral glucocorticoids, non-steroidal anti-inflammatory drugs, or disease modifying antirheumatic drugs. With different drugs, there have been reports that skin lesions are healed and the number of painful or swollen joints reduced or stabilised. However, nearly all patients, irrespective of age, end up with contractures of the fingers and, a small number, with a destructive arthropathy. To our knowledge, complete remission has only been described in two patients treated with glucocorticoids9 and low dose methotrexate.10 This may indicate that, so far, only the natural history of FR has been studied.
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