Etiologies for childhood-onset diffuse joint contractures encompass a large group of inherited disorders and acquired diseases, in particular a subtype of juvenile idiopathic arthritis called "dry polyarthritis, "dermatomyositis, and systemic sclerosis. We report on 2 boys, aged 5 and 8 years, who developed acquired symmetric painless joint contractures preceding the development of superficial plaques of morphea by 7 to 13 months. There was no other clinical involvement, biological inflammation, or autoantibodies. No urinary mucopolysaccharidosis was seen. In both patients, wrist MRI showed no joint effusion, no bone erosion, and no or mild synovial thickening with slight enhancement after gadolinium infusion. One patient underwent a synovial biopsy, which showed dense fibrosis with a sparse inflammatory infiltrate, similar to the pathologic pattern observed in the skin biopsy. With methotrexate and systemic steroids, joint contractures slowly improved in the first patient and remained stable in the second. These 2 cases suggest that fibrous synovitis should be considered in children with acquired diffuse, symmetric, painless contractures and without elevation of acute-phase reactants, even in the absence of cutaneous manifestations. Articular MRI with gadolinium and careful cutaneous examination at onset and during follow-up should provide clues for diagnosing this entity.