Xanthomas: a marker for hyperlipidemias.
Xanthomas are deposits of lipids in the skin and sometimes of the subcutaneous tissue that are expressed clinically as yellowish papules and plaques, nodules, and tumors. They are often, but not always, a consequence of hyperlipidemia. In these cases, a meticulous work-up nearly always reveals some disturbance in regards to the metabolism of the lipids-lack of certain lipoproteins, for example. Xanthoma tuberosum and tendinosum occur in persons with familiar hypercholesterolemia, palmar crease xanthoma in familial dysbetalipoproteinemia, plane xanthoma in persons with an underlying lymphoproliferative disorder (or normolipemic), and eruptive xanthoma in those with a genetically-transmitted lipoprotenemia. In sum, each type of xanthoma and any associated abnormality in lipid metabolism can be diagnosed with specificity. Xanthomas are deposits of lipid in the skin or subcutaneous tissue that manifest clinically as yellowish papules, nodules and tumors. They are often associated with hyperlipidemias, although some of them may be normolipemic. Xanthomas result when abnormalities in the transportation of lipids such as cholesterol, triglycerides and phospholipids cause these lipids to be deposited in the skin and being ingested by tissue macrophages. When they are deposited in the walls of arteries, they promote the development of atherosclerosis. Sometimes, by identifying the clinical variant of the xanthoma, the lipoprotein that is deposited and the clinical associations can be predicted. This discussion will focus on those xanthomas associated with hyperlipidemias.