[Skin disease in Basedow's disease]

Two cases of Graves' (Basedow) dermopathy are reported. In one case pretibial myxoedema was localized on the external surface of the legs down to insteps. In the second case a diffuse form involved both legs and was characterized by wrinkles and peau d'orange appearance at the ankles. In both cases a biopsy confirmed the diagnosis of Graves' dermopathy, showing diffuse areas of amorphus substance infiltrating the derma and fragmentation of collagen fibers. According to the literature, the skin lesions were associated with ophtalmopathy. Thyrostatic therapy affected ophtalmopathy in one of the patients, while pretibial myxoedema regressed in both. The pathogenesis of pretibial myxoedema is not completely clear yet, although dermopathy, along with ophtalmopathy and acropachy, is considered to be an extrathyroidal manifestation of Graves' disease related to bioassayble antibodies anti-TSH receptor. A class of dermopathy-associated antibodies (DAAb) has been identified. It seems to be a reliable biological marker for pretibial myxoedema since it is nearly absent in patients with ophtalmopathy and without dermopathy. Since DAAb does not stimulate human fibroblasts in culture, the role of DAAb in the development of Graves' dermopathy is still to be found.