Xanthomatosis Associated with the Defect of Apo E and Type III Hyperlipoproteinemia

We examined the xanthoma of a patient's skin with hyperlipoproteinemia type III histologically, histochemically, PAG electrophoretically and electronmicroscopically. : A 12-year-old Japanese girl had developed semispherical papules, which were slightly yellowish and brownish in color had been increasing in size and number for these 10 years. The broad midband Lps was detected by PAG-disc electrophoretograms in serum Lps. Traces of Apo E were not detected in the VLDL of the patient by SDS-PAGE or isoelectric focussing. Before clofibrate-administration, serum lipid was 403 mg/dl in TC and 181 mg/dl in TG. Histopathologically numerous xanthoma cells were found in whole dermis. Electronmicroscopically cytoplasm of these xanthoma cells contained many lipid vacuoles. Some of these vacuoles which were not limited by a distinctive membrane were limited by topographically close finger-print figure of membrane and contained neither lamenated nor myelinated bodies. 44 days after clofibrate-administration, we noticed the disappearance of xanthelasma and partial regression of the papules. Serum lipid was 294 mg/dl in TC, 140 mg/dl in TG. Histopathologically it was found that some xanthoma cells and spindle shaped cells were aggregated around capillaries. Electronmicroscopically xanthoma cells were packed with numerous dense bodies, myelinated bodies and/or vacuolated bodies, which seems to indicate that various stages of digestion of lipids are occurring in them. Some of the spindle shaped cells, packed with numerous dense bodies and vacuolated bodies, resembled macrophages. Others, packed with dense bodies, vacuolated bodies and thick myofilaments, resembled smooth muscle cell-like cells.