Case 4. Malakoplakia of colon (36 y-o M)
         
   
Colon biopsy for a soft submucosal lesion with a polypoid projection
   
         
   
Key words : malakoplakia, E. coli, Michaelis-Gutmann body
   
     
 
     
Michaelis-Gutmann bodies seen in the cytoplasm of foamy macrophages forming xanthogranuloma (HE)   Michaelis-Gutmann bodies are PAS-positive.
     
 
     
Hemosiderin deposition seen in Michaelis-Gutmann bodies (Berlin blue)   E. coli antigens seen in Michaelis-Gutmann bodies (immunostaining)