label: Sea-blue histiocytosis
label_lc: sea-blue histiocytosis
description: An abnormality of histiocytes, in which the cells take on a sea blue appearance due to abnormally increased lipid content. Histiocytes are a type of macrophage. Sea-blue histiocytes are typically large macrophages from 20 to 60 micrometers in diameter with a single eccentric nucleus whose cytoplasm if packed with sea-blue or blue-green granules when stained with Wright-Giemsa.