Localized and systemic scleroderma show different histological responses to methotrexate therapy

Although morphoea (localized scleroderma) and systemic sclerosis are distin ct disease entities, the skin lesions show identical histological character istics and both diseases respond favourably to low-dose treatment with meth otrexate (MTX), The aim of this study was to find out whether MTX treatment induces different histological response patterns in these two diseases. In seven patients with morphoea and eight with systemic sclerosis, skin biops ies were taken before and after 24 weeks of treatment with low-dose MTX. In the centre and active margin of morphoea lesions, a significant reduction in tenascin staining was seen after 24 weeks of treatment, in contrast to s ystemic sclerosis, The numbers of mast cells decreased in the active margin of morphoea lesions, whereas in systemic sclerosis no significant change w as seen after MTX therapy, Epidermal proliferation and staining of heparan sulphate proteoglycans showed no changes. Although skin lesions from both d iseases respond clinically to treatment with MTS, systemic sclerosis shows no change in the immunohistochemical parameters investigated, whereas morph oea does, This difference in dynamic pattern suggests that the apparently s imilar lesions in localized and systemic sclerosis are not identical. Copyr ight (C) 2000 John Wiley & Sons, Ltd.