Case 20. Giardiasis (30 y-o M)
         
    Duodenal biopsy from an Iranian male complaining of abdominal discomfort and mild diarrhea    
         
   
Key words : 
Giardia lamblia, lymphoid hyperplasia, intraepithellial lymphocyte, cholecystitis    
         
   
zoonosis
   
     
 
     
Chronic active duodenitis with lymphoid follicle formation (HE)   Chronic active duodenitis with increased intraepithelial lymphocytes and surface infection of G. lamblia (HE)
     
 
     
Trophozoites of G. lamblia seen in the lumen of the duodenal mucosa (HE, high power)   Distribution of CD3-positive T-cells in the duodenal mucosa showing marked increase of intraepithelial lymphocytes (immunostaining)
     
 
     
The intraepithelial lymphocytes are predominantly positive for CD8, a marker of killer T-cells (immunostaining).   CD79a-positive B-cells are seen in the lymphoid follicle, in association with focal intraepithelial clustering (immunostaining).
     
 
     
Reference case 20A
Trophozoites of Giardia lamblia seen in bile. Flagellated and binucleated giardial trophozoites are co-infected with bacteria in the gallbladder (Giemsa).
  Reference case 20A
Trophozoites of Giardia lamblia seen in bile. Binucleated giardial trophozoites in the bile (Papanicolaou).