A case report of EMO syndrome showing localized hyperhidrosis in pretibial myxedema.

We describe here a case of EMO syndrome, which is defined as a combination of exophthalmos, pretibial or localized myxedema, and hypertrophic osteoarthropathy. A 34-year-old Japanese man with Graves' disease developed the characteristic eye changes. He showed 22 mm protrusion of both eyes and hypertrophy of the right lateral rectus muscle as well as both superior rectus muscles by computerized tomography. He subsequently developed lightly erythematous, indurated, nonpitting, peau d'orange plaques and nodules on his lower legs. Finally, he developed Graves' acropathy with hypertrophic osteoarthropathy in the metacarpal bones. Histological examination of myxedematous skin showed typical deposition of mucin accompanied by changes in the amount and distribution of elastic fibers. In addition, the lesional skin showed localized hyperhidrosis, a rarely reported complication of pretibial myxedema. We speculate that this hyperhidrosis of the lesional skin was brought about by stimulation of peripheral sympathetic nerves by surrounding mucin deposition, in the setting of poorly controlled hyperthyroidism.