Sea-blue histiocytosis associated with hyperlipidaemia.

A patient with sea-blue histiocytosis in spleen and bone marrow with an accompanying hyperlipidaemia is described. The hyperlipidaemia was due to an increase in "free" cholesterol, lecithin, and triglycerides. Despite these findings lecithin-cholesterol acyl transferase activity was normal. Although the precise biochemical defect was not identified, there was a failure of transport of cholesterol from chylomicrons in vitro. We propose that the sea-blue histiocyte is a marker, in some cases, of abnormal lipid metabolism.