Patterns of hepatic injury

Patterns of Hepatic Injury

Degeneration & Intracellular Accumulation
Degeneration
mild to moderate  hepatocyte swelling  reversible
severe damage  ballooning degeneration  irregularly clumped organelles and large clear spaces
Accumulations in Viable Hepatocytes
iron and copper
triglyceride fat deposits  STEATOSIS
microvesicular – multiple, tiny (e.g. acute fatty liver of pregnancy, alcoholic fatty liver
macrovesicular – single large deposit displacing the nucleus (e.g. obesity, diabetes, alcoholism)

Macrovesicular steatosis

Iron stain using the Prussian Blue Reaction (x400). Hemosiderin granules stain as dark blue, coarse granules.

Patterns of Hepatic Injury

Necrosis and Apoptosis
Types:
Ischemic coagulative necrosis – “mummified” liver cells with lysed nuclei
Apoptotic cell death – shrunken, pyknotic & intensely eosinophilic cells with fragmented nuclei
Lytic necrosis – outcome of ballooning degeneration  (+) shards of cellular debris
Liquefactive necrosis - abscesses

Necrosis (left lower) is around the centrilobular area. The periportal area is viable.

Ischemia of centrilobular area resulting in coagulative necrosis of hepatic cords. (Preservation of cellular contour with disappearance of nucleus) Some viable hepatocytes with nucleus are seen in the upper middle and upper right areas.







Bridging confluent lytic necrosis in severe chronic viral hepatitis B. Inflamed portal tract ‘bridged’ through area of necrosis with centrilobular area (lower left). The upper right part corresponds to an area of extensive lytic necrosis.

Patterns of Hepatic Injury

Necrosis and Apoptosis
Distribution:
Centrilobular – most common; immediately around terminal hepatic vein
Mid-zonal and periportal – rare
Degree of involvement:
Focal or spotty – limited to scattered cells within hepatic lobules
Interface hepatitis – between periportal parenchyma & inflamed portal tracts
Bridging necrosis – span adjacent lobules
Submassive necrosis – entire lobules
Massive – most of the liver





Interface hepatitis

Patterns of Hepatic Injury

Inflammation
Hepatitis
Influx of acute and chronic inflammatory cells
Regeneration
Occurs in all but the most fulminant hepatic diseases
Features:
Mitosis
Thickening of hepatic cords
Disorganization of parenchymal structure

Patterns of Hepatic Injury

Fibrosis
Consequence of inflammation or direct toxic insult to liver
Irreversible
May eventually subdivide liver into nodules of proliferating hepatocytes surrounded by scar tissue  CIRRHOSIS