Pretibial Myxedema Presenting as Severe Elephantiasis

Elephantiasis is a symptom characterized by the thickening of the skin and underlying tissues in the legs. Pretibial myxedema (PTM) is a non-frequent manifestation of autoimmune thyroiditis, particularly Graves' disease. Lesions of myxedema occur most commonly on the pretibial surfaces, also develop at sites of previous injury or scars and other areas. A 49-year-old male presented with severe elephantiasis on the both pretibial areas, dorsum of the feet, ankles and toes. Twenty years previously, he had received radioactive iodine treatment for thyrotoxicosis. Laboratory tests showed that the patient's thyroid function was normal, but the level of thyroid stimulating hormone (TSH) receptor antibodies was very high (> 40 IU/L). The biopsy confirmed PTM. Interestingly, the connective tissue was stained with the TSH receptor antibodies in the deep dermis. Elephantiasic PTM is a severe form of the myxedema and there is few reported case. We report a rare case of PTM with appearance of severe elephantiasis.