Image Description
The presence of amebic trophozoites in the inflammatory infiltrate within colonic biopsies confirms the diagnosis of amebic colitis. They are round or ovoid, measuring 10-20 μ in diameter, and surrounded by clear space (an artifact). The have abundant vacuolated cytoplasm and a small round nucleus. Erythrophagocytosis is usually present. With PAS stain, the trophozoites stain magenta. Due to their morphologic resemblance, trophozoites may be mistaken for macrophages.