Whipple's disease: the first Japanese case diagnosed by electron microscopy and polymerase chain reaction.

A 52-year-old man presented with diarrhea and 20 kg weight loss in one year. Enteroscopy showed diffuse yellow-white shaggy mucosa in the duodenum and jejunum. Biopsies of the duodenal mucosa revealed massive infiltration within the lamina propria by foamy macrophages strongly positive for periodic acid-Schiff stain. Electron microscopy demonstrated numerous bacilli within macrophages of the lamina propria. Tropheryma whipplei DNA was detected by polymerase chain reaction. The definitive diagnosis of Whipple's disease was made. Antibiotic therapy dramatically improved his clinical picture. This is the first Japanese case with Whipple's disease diagnosed by electron microscopy and polymerase chain reaction.