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Pretibial myxedema

Copyright © 2010 Society of Hospital Medicine

An 83‐year‐old female reported increased swelling of her legs over the past 2 years. She noted temperature intolerance, low energy, and constipation, but denied any hair loss or nail changes. On exam, she had marked bilateral lower extremity edema that was predominately nonpitting. Overlying the edema there were thickened, well‐defined plaques with a peau d'orange appearance surrounded by brown, thin plaques on the pretibial areas sparing the dorsum of the feet (Figure 1). A punch biopsy was obtained and demonstrated increased deposition of mucin throughout the dermis along with fragmentation and increased numbers of elastic fibers consistent with a diagnosis of pretibial myxedema. Measured thyrotropin level was elevated at 3.9 U/mL (normal, 0.3‐3.8 U/mL), consistent with hypothyroidism. This is a severe example of pretibial myxedema, or infiltrative dermopathy, which can occur, more commonly, in the setting of Graves' disease or, in rare circumstances, hypothyroidism.1 Myxedema results from the accumulation of hyaluronic acid and chondroitin sulfate in the dermis.2 Treatment is difficult and includes topical glucocorticoids under occlusion and, if indicated, thyroid corrective therapy.3

Figure 1

Pretibial myxedema. Note thickened, well‐defined plaques with a peau d'orange appearance surrounded by brown, thin plaques on the pretibial areas sparing the dorsum of the feet.

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