Xanthelasma is usually seen in clinical situations characterized by abnormally high serum cholesterol or triglyceride levels, which are usually accompanied by disturbance of lipoprotein metabolism. The presence of xanthelasma in patients with thyrotoxicosis is highly unusual. Of three patients studied with such an association, there was only one abnormal finding in a diabetic glucose tolerance test. Lipid studies were within normal limits in all of the patients. Another patient also presented unquestionable evidence of atherosclerotic and rheumatic heart disease.
Martínez-Rovira GR. Xanthelasma in Association With Hyperthyroidism. JAMA. 1968;206(5):1081-1083. doi:10.1001/jama.1968.03150050069020