Other common viruses that cause hepatitis are Epstein-Barr virus (EBV), which is also known as infectious mononucleosis, and cytomegalovirus (CMV). Both of these viruses present alike with mild acute hepatitis. Although there are histologic features present in a liver biopsy such as sinusoidal lymphocytes and abundant mitosis, they are not alone diagnostic; serologic studies must be performed to determine a definitive diagnosis.
In a late hepatitis episode, a biopsy may be taken to assess the progression of the disease. Common, diagnostic findings are the presence of lymphocytes in portal areas, irregular cell plates, lipofuscin pigment and iron present in the Kupffer cells. A combination of lipofuscin and iron pigments is characteristic of resolving acute hepatitis.