title: Periodic acid-Schiff-negative granulomatous lymphadenopathy in patients with Whipple's disease. Localization of the Whipple bacillus to noncaseating granulomas by electron microscopy.
abstract: The diagnosis of Whipple's disease in a 58-year-old man was based on the finding of periodic acid-Schiff (PAS)-positive foamy macrophages on duodenal biopsy and demonstration of the typical bacilliform bodies by electron microscopy. The patient also had generalized peripheral lymphadenopathy with lymph node biopsy showing PAS-negative noncaseating granulomas. Electron microscopic examination of the lymph node specimen demonstrated a small number of typical bacilliform bodies with localization specifically to the granulomas in the lymph node. This finding of bacilliform bodies within PAS-negative noncaseating granulomas has not been reported previously. Localization of the Whipple bacillus specifically to noncaseating granulomas suggests that some patients with the disease may manifest a delayed hypersensitivity reaction to the bacillus.
mesh_terms: D001706:Biopsy; D001853:Bone Marrow / Q000378:metabolism / Q000648:ultrastructure; D004386:Duodenum / Q000378:metabolism / Q000648:ultrastructure; D006099:Granuloma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000648:ultrastructure; D008206:Lymphatic Diseases / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D010503:Periodic Acid-Schiff Reaction; D008061:Whipple Disease / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology