Nonalcoholic steatohepatitis masquerading as autoimmune hepatitis.

Nonalcoholic steatohepatitis is an increasingly recognized clinicopathologic condition. We report two cases of nonalcoholic steatohepatitis in middle-aged Japanese women whose clinical and laboratory data mimicked autoimmune hepatitis. Histologic findings of both cases were definite steatohepatitis with portal and pericellular fibrosis. Both patients' HLA-DR haplotypes were DR4 and DR2, which are frequently observed in Japanese patients with autoimmune hepatitis. Our cases suggest a diversity in the pathogenesis of nonalcoholic steatohepatitis.