1) A non-neoplastic disorder characterised by a localised collection of histiocytes containing lipid. Xanthomas usually occur in the skin and subcutaneous tissues, but occasionally they may involve the deep soft tissues.

2) A fatty irregular yellow patch or nodule containing lipid-filled foam cells that occurs on the skin (as of the eyelids, neck, or back) or in internal tissue and is associated especially with disturbances of lipid metabolism.