title: Pigments of the gastrointestinal tract: a comparison of light microscopic and electron microscopic findings.
abstract: It is now apparent that light microscopy and histochemistry failed to identify correctly the nature and composition of pigments in various gastrointestinal tract melanoses. In most instances it was thought that the pigment was melanin or a melanin-like substance. Electron microscopy (EM) and electron-probe energy dispersive x-ray analysis have rectified these errors and have shown the following: in melanosis coli the pigment granules contain lipofuscin; in melanoses ilei the pigment granules may contain either silicates and titanium or hemosiderin; and in melanosis duodeni the pigment granules contain iron sulfide. In melanosis esophagi it is not clear what the pigment is; it could be melanin or lipofuscin.
authors.affiliation: Department of Laboratory Medicine, Ottawa Civic Hospital, Ontario, Canada.
authors.forename: F N
authors.initials: FN
authors.lastname: Ghadially
authors.forename: V M
authors.initials: VM
authors.lastname: Walley
mesh_terms: D004064:Digestive System / Q000737:chemistry* / Q000648:ultrastructure*; D005767:Gastrointestinal Diseases / Q000378:metabolism / Q000473:pathology*; D006485:Hemosiderin / Q000032:analysis; D006801:Humans; D058085:Iron Compounds / Q000032:analysis; D008062:Lipofuscin / Q000032:analysis; D008543:Melanins / Q000032:analysis; D008548:Melanosis / Q000378:metabolism / Q000473:pathology*; D008854:Microscopy, Electron; D010860:Pigments, Biological / Q000737:chemistry*; D017640:Silicates / Q000032:analysis; D014025:Titanium / Q000032:analysis
chemical_list: D058085:Iron Compounds; D008062:Lipofuscin; D008543:Melanins; D010860:Pigments, Biological; D017640:Silicates; D006485:Hemosiderin; D014025:Titanium