| Summary: | Focal granulomatous inflammation developed in the livers of five 10-week-old male
Sprague-Dawley rats. The characteristic features of this lesion were the
presence of foreign body multinucleated giant cells engulfing calcium deposits
and site-specific development in a fissure formed in a sub-lobation in the left
lobe or interlobar fissure of the medial lobe of the liver. To clarify the
pathogenesis of this lesion, rat livers showing abnormal sub-lobation or lobar
atrophy, rat livers in an acute dermal toxicity study and guinea pig livers in a
skin sensitization test were also examined histologically. Consequently, the
present lesion was considered to be a reactive change against calcium that was
dystrophically deposited in the area of hepatocellular necrosis due to delayed
circulatory disturbance caused by external pressure or extension force.
Granulomatous lesions like in the present cases should be differentiated from
those caused by evident exogenous pathogens such as chemicals or
microorganisms.
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