Tuberous xanthomas are firm yellow-red nodules that occur over sites of pressure: they usually indicate the presence of hyperlipidaemia type 3 (Type III hyperlipoproteinaemia). They start as small xanthomas, usually over the extensor aspects of the elbows and knees, but can develop into quite exuberant exophytic lesions several centimetres in diameter and height. They can develop over other pressure sites particularly the heels and plantar surfaces of the feet.