Relationship of steatosis grade and zonal location to histological features of steatohepatitis in adult patients with non-alcoholic fatty liver disease

Background/Aims: The relationship between severity and zonal location of steatosis and the presence of steatohepatitis and various histological features that define NASH has not been formally studied. Methods: We conducted a study to examine the relationship of severity and zonal location of steatosis to the presence of NASH and to other histological features that define NASH in adult patients with NAFLD. Steatosis was graded as mild, moderate or severe. We examined the relationship between severity and zonal location of steatosis and the following: lobular inflammation, presence of ballooning, Mallory bodies, fibrosis score, and definite steatohepatitis. Results: Mild, moderate and severe steatosis was present in 44%, 31% and 25% of biopsies, respectively. Definite steatohepatitis was present in 59% and advanced fibrosis in 29% of liver biopsies. Increasing levels of steatosis severity were positively associated with lobular inflammation (p < 0.0001), zone 3 fibrosis (p < 0.001), and definite steatohepatitis (p = 0.02), but were unrelated to ballooning, Mallory bodies, or advanced fibrosis. As compared to zone 3 steatosis, pan-acinar steatosis was more often associated with ballooning, Mallory bodies, and advanced fibrosis. Conclusions: Patients with severe steatosis are more likely to have steatohepatitis. More studies are needed to confirm this observation and to explore its significance.