Normolipidemic planar xanthomatosis associated with benign monoclonal gammopathy

This report describes a patient with advanced planar xanthomatosis and benign monoclonal gammopathy who had normal plasma concentrations of cholesterol and triglycerides (TG). Decreased electrophoretic mobilities of very low density lipoprotein (VLDL), intermediate density lipoproteins (IDL) and chylomicrons were found. No changes in electrophoretic mobility were found for low density lipoprotein (LDL) and high density lipoproteins (HDL). The patient's disease was associated with a progressive decline in plasma-TG and VLDL-TG over a 2 yr period. He also appeared to develop an increased rate of clearance of VLDL-TG and chylomicrons. These changes in the metabolism of TG-containing lipoproteins were unaccompanied by alterations in the synthesis of either cholesterol or bile acids. The observations in this patient led us to the conclusion that his normal to low levels of VLDL-TG could be explained by both enhanced tissue uptake and increased lipolysis of VLDL-TG. The most likely explanation for these findings is that the patient had immune complexes between his TG-rich lipoproteins and an abnormal monoclonal gamma globulin. This patient is another example of an expanding group of subjects in whom xanthomatosis can develop without hyperlipidemia.