Fibroblastic rheumatism: an addition to fibromatosis.

Fibroblastic rheumatism (FR) is a rare rheumatologic entity of unknown etiology. It is characterized by symmetrical polyarthritis associated with multiple cutaneous nodules. Bone erosion can occur as the disease progresses and destructive arthropathy is not rare. We report on an 18-year-old man with FR who presented a 6-year history of cutaneous nodules localized at para-articular sites with only minimal oligoarthralgia on exertion. There was no visceral involvement, and all the routine and immunological tests were normal. The diagnosis of FR was confirmed by histological examination of a nodule, which composed of myofibroblastic proliferation and thickened collagen fibers. Most skin lesions resolved after treated with IFN-α, however there was sequelae of permanent disability due to the progressive bone erosion despite weekly methotrexate treatment.