Entamoeba coli

• Mature, infective cyst in stool specimen, Trichrome-stained
• Large, spherical or ovoidal shaped cyst, 15-25 micrometer in diameter
• Usually contains 8 nuclei, but 16 nucleated cyst can be found sometimes
• Each nuclei has eccentric karyosome
• Peripheral nuclear chromatin asymmetrically distributed, giving an uneven thickness look to nuclear membrane
• Sometimes, chromatoid body with splintered ends can be seen in cytoplasm