Figure 22.

Concentrated bile pigments in a cell block preparation of liver abscess clinically suspected of being amebic infection. (a): H&E and (b): immunostaining using a monoclonal antibody EHK153 against Entamoeba histolytica. Brown-colored structures of concentrated bile pigments somewhat resemble strongly immunoreactive amebic trophozoites. The entamoeba antigen must be judged as negative in this case. Careful comparison with H&E histology is needed to avoid falsely judging these as positive immunohistochemical signals.