title: Ultrastructural evidence of Tropheryma whippelii in PAS-negative granulomatous lymph nodes.
abstract: The presence of Tropheryma whippelii was demonstrated in the PAS-negative mesenteric granulomatous lymph nodes of a patient affected by Whipple disease. Ultrastructurally a few bacteria, enclosed by a membrane characteristic of Tropheryma whippelii, were found in the extracellular spaces and remnants of bacteria were found in the phagocytic vacuoles of macrophages. The scarce number of bacilli, probably due to the fact that the disease was at an initial phase, could explain the absence of PAS positivity. This case confirms the role of the electron microscopy in the diagnosis of Whipple disease, especially for extra-intestinal lesions and at the initial phase of the disease, when the characteristic PAS-positive macrophages can be absent.
authors.affiliation: Department of Pathology, Ospedale di Circolo, Varese, Italy. anapat@ospedale.varese.it
authors.forename: Giovanna
authors.initials: G
authors.lastname: Finzi
authors.forename: Francesca
authors.initials: F
authors.lastname: Franzi
authors.forename: Fausto
authors.initials: F
authors.lastname: Sessa
authors.forename: Claudio
authors.initials: C
authors.lastname: Mastaglio
authors.forename: Carlo
authors.initials: C
authors.lastname: Capella
mesh_terms: D039903:Actinobacteria / Q000302:isolation & purification* / Q000648:ultrastructure; D000890:Anti-Infective Agents / Q000627:therapeutic use; D006099:Granuloma / Q000382:microbiology / Q000473:pathology*; D006529:Hepatomegaly / Q000382:microbiology / Q000473:pathology; D006801:Humans; D008198:Lymph Nodes / Q000382:microbiology* / Q000648:ultrastructure; D008206:Lymphatic Diseases / Q000382:microbiology / Q000473:pathology; D008264:Macrophages / Q000382:microbiology / Q000648:ultrastructure; D008297:Male; D008643:Mesentery / Q000473:pathology; D008875:Middle Aged; D010503:Periodic Acid-Schiff Reaction; D013163:Splenomegaly / Q000382:microbiology / Q000473:pathology; D016896:Treatment Outcome; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use; D008061:Whipple Disease / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology*
chemical_list: D000890:Anti-Infective Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination