Xanthoma cells

Xanthelasma is caused by an infiltration of the dermis by xanthoma cells, which are benign histiocytes that imbibe lipids. The condition may occur independently, without associated systemic disease, or may be a manifestation of hypercholesterolemia or other associated disturbance of lipid metabolism. 

Fig. 13.2 Chronic cholestasis with granuloma-like accumulation of hpid-laden macrophages (xanthoma cells) (HE)...

In Apo E-deficient animals fed a normal chow diet, fatty streaks are first observed in the proximal aorta at 10 to 12 weeks (15). The xanthoma that forms in the intima contains foam cells and is often called the early atherosclerotic lesion and is critically dependent on monocytes. Smooth muscle cells (SMCs) arrive in the intima at approximately 15 weeks and form a fibrous cap around 20 weeks (16). By 36 weeks, lumen narrowing occurs in the external branches of the carotid artery (incidence -75%), but the lumen size is maintained in the aorta. Lumen narrowing, or stenosis, does not correlate with plaque size but... 

Foam cells. Cells with a peculiar vacuolated appearance owing to the presence of complex lipoids such cells are seen notably in xanthoma. 

D. Lipidland. As the liver is not turning out glucose, alternate sources of energy must be increased. Triglycerides break down in fet cells to release fatty acids, with elevation of serum lipids. There may be fetty deposits (xanthomas) in various parts of the body. The excess pyruvate (pyruvic acid) and lactate (lactic acid) result in a serum acidosis. 

A. Familial lipoprotein lipase deficiency (Type I lipoprotein pattern on electrophoresis). Serum triglycerides become elevated with particular elevation of chylomicrons. Tliere are xanthomas, rather than atherosclerosis. Pancreatitis may result from the action of pancreatic lipase on these elevated chylomicrons, with resultant excess triglyceride breakdown in the pancreas, pancreatic injury, and release of more pancreatic lipase. (Note that the body contains different kinds of lipases. There is a pancreatic lipase, which is a digestive enzyme a lipoprotein lipase, which is an extracellular enzyme that breaks down plasma triglycerides, thereby enabling fatty acids to enter cells and an intracellular lipase that breaks down stored triglycerides). 

Intrahepatic biliary atresia is characterized by a paucity of intrahepatic bile ducts. Jaundice usually appears within the first few days of life. Serum bilirubin is elevated and serum cholesterol may be very high and lead to the formation of xanthomas. The hepatic histology is nonspecific, showing bile duct paucity, giant cells, inflammation, and fibrosis. Survival into adolescence is common, although growth is usually retarded. 

---