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PIGMENTARY DISORDERS
The hepatocytes and Kupffer cells here are full of granular brown deposits of hemosiderin from accumulation
of excess iron in the liver. The term "hemosiderosis" is used to denote a relatively benign accumulation of iron. The term "hemochromatosis" is used when organ dysfunction occurs. The iron accumulation may lead to a micronodular
cirrhosis (so called "pigment" cirrhosis).
A Prussian blue iron stain demonstrates the blue granules of hemosiderin in hepatocytes and Kupffer cells.
Hemochromatosis can be primary (the cause is probably an autosomal recessive genetic disease) or secondary (excess iron intake or absorption, liver disease, or numerous transfusions). Hemochromatosis leads to bronze
pigmentation of skin, diabetes mellitus (from pancreatic involvement), and cardiac arrhythmias (from myocardial involvement).
The dark brown color of the liver, as well as the pancreas (bottom center) and lymph nodes (bottom right)
on sectioning is due to extensive iron deposition in a middle-aged man with hereditary hemochromatosis (HHC).
HHC results from a mutation involving the hemochromatosis gene (HFE) that leads to increased iron absorption from
the gut. The prevalence is between 1:200 and 1:500 persons in the U.S. About 1 in 10 persons of northern European
ancestry carries the abnormal recessive HFE gene, and most of these are the C282Y mutation.
The Prussian blue iron stain reveals extensive hepatic hemosiderin deposition microscopically in this case
of hereditary hemochromatosis (HH). Note that there is also cirrhosis. Excessive iron deposition in persons with
HH can affect many organs, but heart (congestive failure), pancreas (diabetes mellitus), liver (cirrhosis and
hepatic failure), and joints (arthritis) are the most severely affected.
The pale golden brown finely granular pigment seen here in nearly all hepatocytes is lipchrome (lipofuscin).
One such deposit within a hepatocyte is marked by the arrow. This is a "wear and tear" pigment from the accumulation
of autophagolysosomes over time. This pigment is of no real pathologic importance.
The yellowish-green accumulations of pigment seen here are bile. Most often this is due to extrahepatic biliary
tract obstruction. However, bile may also accumulate in liver (called cholestasis) when there is hepatocyte
injury.
Here is an example of intrahepatic obstruction with a small stone in an intrahepatic bile duct. This could
produce a localized cholestasis, but the serum bilirubin would not be increased, because there is plenty of
non-obstructed liver to clear the bilirubin from the blood. However, the serum alkaline phosphatase is increased
with biliary tract obstruction at any level.
НАПИСАТЬ
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