[Clinical picture of pretibial myxedema and new aspects of diagnosis and pathogenesis].

We have reported on two cases of pretibial myxedema. In one patient, the pretibial myxedema developed symmetrically half a year after the appearance of endocrine exophthalmos. Recently, acropachy developed as well. In the second case, the pretibial myxedema arose unilaterally in an old cicatricial area, six years after the onset of endocrine exophthalmos. In this syndrome, the development of the whole group of symptoms, dermopathy, ophthalmopathy, and osteopathy at the same time is very rare. The clinical picture is seen in thyroid disorders, as a rule occuring in hyperthyroidism, rarely in hypothyroid or euthyroid states. Apparently, the development of the symptoms does not depend on thyroid hormone production. One of our patients showed conspicuous hyperthyroidism, the other, thyroxin deficiency. The thyreohypophyseal feedback mechanism in this syndrome was examined for the first time by means of TRH stimulation tests. In both patients, thyroid auto-antibodies indicative of autoimmune thyroiditis were demonstrated. A high activity of long acting thyroid stimulator was measured in the one patient's serum.