Case 49.  Amebic liver abscess (38 y-o M)
         
   
Needle aspirate from liver abscess in AIDS
   
         
   
Key words :  Entamoeba histolytica, liver abscess, AIDS
   
         
   
opportunistic infection, sexually transmitted infection
   
     
 
     
Unfixed aspirate contains a few amebic trophozoites showing an ameboid movement in the necrotic background.   Papanicolaou-stained preparation reveals light green-stained trophozoites. In the background, necrotic debris and nuclear dusts are observed.
     
 
     
Oil immersion observation discloses a centrally located nucleus with peripheral chromatin condensation and the double-layered cytoplasm (thick-stained inner "endoplasm" vs. light-stained outer "ectoplasm") (Papanicolaou).   Cell block preparation of the aspirate reveals a few eosinophilic trophozoites in the background of karyorrhectic neutrophils (HE).
     
 
     
Amebic liver abscess (38 y-o M)
Needle aspirate from liver abscess in AIDS. PAS stain clearly demonstrates PAS-positive trophozoites. The background neutrophils are non-reactive, because of glycogen consumption (cell block).
  Amebic liver abscess (38 y-o M)
Needle aspirate from liver abscess in AIDS. Monoclonal antibody specifically identifies the amebic trophozoites (immunostaining using a cell block).
     
   
     
Reference case 49A
Sagittal sections of the autopsied liver with multifocal amebic abscess provoking left pyothorax, in case of advanced gastric cancer (45 y-o M). Opportunistic infection in an HIV-negative cachectic patient. The abscess content is traditionally expressed as anchovy paste-like. Trophozoites are not infective, so that the biohazard at autopsy is low.