Liver Pathology Update

Comparing morphometric, biochemical, and visual measurements of macrovesicular steatosis of liver.
Li M, Song J, Mirkov S, Xiao SY, Hart J, Liu W. Hum Pathol. 2011 Mar;42(3):356-60. (CUMC Full Text PDF)

The authors measure the degree of steatosis in liver samples by biochemical measure of fat content (weight percentage of fat) and digital morphometric analysis (percentage of areas occupied by fat) and compare these with traditional ("visual") pathologic evaluation. Biochemical and digital analyses generated similar results, while "visual" estimates systematically yielded values approximately four times higher than the other two methods (but with highly reproducible values among 3 pathologists).  The fact that different methods yield different absolute values and percentages for "fat content" should come at no surprise. In this study, for instance, the visual assessment evaluated the "proportion of hepatocytes involved by macrovesicular steatosis". This is in sharp contrast with what is being measured biochemically (i.e. total fat content, regardless of cellular location or droplet size, using the entire tissue fragment - portal tracts and fibrous septa included - as denominator). As for digital analysis, it is generally just as accurate as the individual selecting the fields and operating the software. The excellent intra- and interobserver agreement among the three study pathologist is noteworthy as it contradicts previous studies (see Ann Surg 2009;250(5):691-7).