PAS with hematoxylin counterstain. The trophozoites measured between 11 and 16 microns in length and contained a single, large vesicular nucleus and abundant, densely packed cytoplasmic vacuoles. Frequent trophozoites contained a large cytoplasmic vacuole of homogeneous, PAS positive eosinophilic material compressing the nucleus to the periphery of the cell. Cysts were not observed. Trophozoites within remnants of sinusoids in necrotic parenchyma.
Necrotic tissue consists of eosinophilic stroma and cell debris with pyknotic nuclei.
The viable parenchyma had prominent hepatic lipidosis with mild, multifocal perivascular and periportal infiltrates of lymphocytes, plasma cells, and heterophils. Heterophils were also prominent within vessels. Trophozoites and inflammatory infiltrates were most frequent within the viable tissue adjacent to the necrosis. Small clusters of heterophils were occasionally infiltrating the necrotic parenchyma. Rare bacterial rods were present among the necrotic cell debris but not observed in the viable parenchyma.