Grade 1: Some portal inflammation but no real interface hepatitis.
Grade 2: At this portal triad, there is a slightly more significant inflammatory process along with a prominent lymphoid follicle.
Grade 2: There is also focal mild lobular inflammation.
Grade 3: There is a more prominent portal infiltrate along with a definite moderate interface hepatitis at this portal triad.
Grade 3: Another image of moderate interface hepatitis with piecemeal necrosis.
Grade 3: The lobular inflammation is more pronounced with grade 3 and has noticeable hepatocellular damage.
For a liver biopsy with chronic hepatitis (hepatitis B, hepatitis C and autoimmune hepatitis), the pathology report should clearly state the degree of inflammatory activity (grade) and degree of fibrosis (stage). There are numerous grading and stage systems devised by experts (i.e. Scheuer, Knodell), and this author prefers due to its simplicity, the system by Batts and Ludwig.
In the Batts and Ludwig schema, the grade is determined by two features: interface hepatitis and lobular inflammation.1
Grade 0: Portal inflammation only without activity.
Grade 1: Minimal activity with minimal/patchy interface hepatitis and minimal spotty necrosis.
Grade 2: Mild interface hepatitis involving some or all portal tracts and mild hepatocellular damage
Grade 3: Moderate interface hepatitis involving all portal tracts and moderate (noticeable) hepatocellular damage.
Grade 4: Severe interface hepatitis (may have bridging necrosis) and severe diffuse hepatocellular damage.
Note that helpful diagnostic features for chronic hepatitis C infection include lymphoid aggregates, bile duct damage and macrovesicular steatosis. Lymphoid aggregates can be seen in up to 50% of cases (Cheng, Kumar).
Batts KP, Ludwig J. Chronic Hepatitis: An Update on Terminology and Reporting. Am J Surg Pathol 1995;19:1409-17.
Cheng L, Bostwick DG, eds. Essentials of Anatomic Pathology. 2nd Ed. Totowa, NJ: Humana Press; 2006: 1374.
Kumar V, Abbas AK, Fausto N. Robbins and Cotran Pathologic Basis of Disease. 7th Ed. Philadelphia, PA: Elsevier; 2005: 899.