Xanthoma Tuberosum is a type of xanthoma that I occasionally encounter in both my The Woodlands dermatology and Conroe dermatology offices. Clinically, Xanthoma Tuberosum appears as a flat or plaque like yellow/brown lesion. They are most commonly located on the knees and elbows but may be found in other anatomic locations. In many cases, Xanthoma Tuberosum is associated with elevated cholesterol levels and may occur with other diseases such as primary biliary cirrhosis and myxedema.