Lipid synthesis in cutaneous xanthoma.

In vitro lipogenesis was studied on the xanthoma tissue from 6 patients with normal plasma lipids and 4 patients with hyperlipidemia. Xanthoma tissue was incubated at 37 degrees C for 6 hr in Krebs-Ringer phosphate buffer containing sodium [14C]acetate. The radioactivity of each lipid class was determined after extraction and separation of lipids. The incorporation of acetate into all major lipid groups was much greater in xanthoma tissue than in control normal-appearing skin. There was no difference in the incorporation pattern of 14C between xanthomas of patients with normal plasma lipids and those of hyperlipidemic patients. The data exemplify considerable in situ lipid synthesis of xanthoma tissue. Although the lipids in xanthomas of hyperlipidemic persons may be derived from plasma, the plasma origin of xanthoma lipids in normolipidemic persons remains to be confirmed, and the contribution of local lipogenesis cannot be ignored. The lipids in cutaneous xanthomas are most likely derived from a multiple input system.