Entamoeba histolytica

Entamoeba histolytica. Cysts in fecal smear (trichrome stain, oil immersion). Four cysts, three of which are mature and one immature and uninucleate, are present in this field. All four cysts contain typical red-staining chromatoid bodies with rounded ends. Note the distinctly larger size of the nucleus in the uninucleate cyst compared with the smaller nuclei of the mature cysts. A single Blastocystis hominis lies adjacent to one of the mature cysts. Note the smaller size of the Blastocystis and the characteristic nucleilike inclusion bodies at the periphery.