title: Unidentified bacterial microorganisms entrapped within blood capillary spaces of tissue from different epidemiological types of Kaposi's sarcoma.
abstract: Tissue specimens of different epidemiological types of Kaposis sarcoma (KS) from various geographical regions were investigated by transmission electron microscopy. Freshly fixed KS biopsies originated from 9 German patients: 3 classic KS cases, 5 AIDS-associated KS cases, and 1 atypical classic KS case. Additionally, KS autopsy material from the brain of a German AIDS patient was examined. Further biopsies came from 29 Ugandan patients: 16 endemic KS cases and 13 AIDS-associated KS cases. While investigating the ultrastructure, we discovered relatively small-sized bacterial microorganisms within blood capillary spaces of tumor tissue from 5 KS cases of different epidemiological type. The microorganisms often occurred in clusters. They were of coccoid-bacillary form and limited by a wrinkled multilayered cell wall. Many of them were encapsulated. They were not observed outside of the capillary lumen. The bacterial structures were often seen attached to capillary endothelial cells, which sometimes showed blistering into the capillary lumen. The observed bacterial microorganisms obviously represented agents of a bloodstream infection and must have been entrapped and accumulated within capillary spaces of KS tissue. The bacteria, which had an almost identical morphology in all 5 KS cases, could not be identified. If they are of pathogenic significance, it remains unknown.
authors.affiliation: Institute of Molecular Virology, GSF-National Research Center for Environment and Health, Neuherberg, Germany.
authors.forename: K H
authors.initials: KH
authors.lastname: Marquart
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000150:complications; D001419:Bacteria / Q000648:ultrastructure*; D016667:Bacterial Capsules / Q000648:ultrastructure; D001706:Biopsy; D002196:Capillaries / Q000382:microbiology*; D004730:Endothelium, Vascular / Q000382:microbiology; D005858:Germany; D006801:Humans; D008854:Microscopy, Electron; D012514:Sarcoma, Kaposi / Q000098:blood supply / Q000150:complications / Q000382:microbiology*; D014454:Uganda