Xanthomata are asymptomatic lesions. The most important of these lesions commonly encountered in practice are those associated with genetically-based disturbances in lipoprotein metabolism, namely, the familial forms of hypercholesterolemia, dyslipoproteinemia, combined hyperlipoproteinemia, and hypertriglyceridemia. Xanthelasma (see Chapter 57) and arcus senilis, a gray ring at the periphery of the cornea, are sometimes seen in these disorders. Palpable and visible lesions appear in several distinctive forms.

Eruptive xanthomata appear suddenly as crops of small, asymptomatic, discrete, dome-shaped papules on the buttocks and thighs. The arms, elbows, knees, and palms may also be involved. Reddish at first, the lesions soon take on a yellowish or yellowish–brown color (Fig. 58-1). Some are surrounded by a reddish halo. The papules may run together to form plaques. Eruptive xanthomata may occur in hyperlipoproteinemias secondary to other metabolic diseases, especially poorly controlled diabetes mellitus.