Amebiasis

Common sites:

• Cecum and ascending colon
• Liver abscesses in 40% affected
• Lung and brain abscesses sometimes

Gross features:

Histologic features:

• amebae look like macrophages but with smaller nucleus
• look for intracytoplasmic RBCs
• they can be found in mucosa and submucosa
• neutrophilic reaction
• flask-shaped ulcers up to the muscularis propria
• few inflammatory cells
• extensive liquefactive necrosis
• normal or mildly inflamed mucosa between ulcers

Immunophenotype:

Marker:	Sensitivity:	Specificity:
PAS

Molecular features:

Other features:

• entamoebae produce stromal lysis enzymes
• clinically, bloody diarrhea