Hepatic abscesses can be bacterial, fungal or amebic (due to Entamoeba histolytica). Bacterial abscesses result from ascending cholangitis and sepsis. Fungal abscesses (such as those due to Candida species) are most common in immunocompromised patients.
Cytologic diagnostic features
- Abundant polymorphonuclear leukocytes and necrotic debris
- Possibly bacteria and fungi in routine stains, but special stains (silver, Gram) and culture are helpful
Amebic abscesses are most common in developing nations. They are usually a sequel of colonic infection by the protozoan Entamoeba histolytica.
Amebic abscess - cytologic diagnostic features
- ‘anchovy paste’ (necrotic debris)
- Little if any acute inflammation
- Amebic trophozoites (resembling histiocytes): round nucleus with peripheral chromatin margination, abundant ovoid cytoplasm containing ingested red blood cells