Pretibial myxedema: pathogenetic features and clinical aspects

Abstract

Pretibial myxedema (PTM) or thyroid dermopathy is a rare extrathyroidal manifestation of Graves' disease. The condition is accompanied by mucinous skin changes, mainly in the anterior tibial surface. Severe forms may lead to lymphatic congestion and disability. Prolonged and intense autoimmune aggression is supposed to be necessary for PTM manifestation. However, data on the role of TSHR antibodies in the development of thyroid dermopathy are very ambiguous; evidence of IGF-1 receptor involvement in the pathogenesis was reported recently. Typically, PTM is localized on the anterior and lateral surfaces of both tibias and can be represented by diffuse, tumorous, plaque-like, or elephantiasic forms. Currently, early diagnostics involves regular preventive examination of the pretibial area. A diagnostic biopsy is indicated only in complex cases. Maintaining euthyroidism, smoking cessation, preventing injuries, and avoiding tight shoes that disturb lymphatic drainage are measures reducing the risk of PTM in GD patients. Currently, there are no accepted clinical guidelines for the diagnosis and treatment of thyroid dermopathy. This review provides the recent scientific data on etiopathogenesis and management of patients with PTM.