Special thanks to my GI attending, Dr. Jessica Tracht, for her awesome tips!
(Pictures/examples to come shortly)
"Fatty Liver Disease"
Steatosis is often referred to as "fatty liver" and can be seen in medical liver biopsies. Steatohepatitis (as the name implies) refers to a fatty liver (STEATO-) also with inflammation of the liver parenchyma (-HEPATITIS). Patients with steatohepatitis often have falsely elevated autoimmune serologies and are often being biopsied for that reason.
Steatosis and steatohepatitis can be caused by:
ASH (alcohol)
NASH (obesity)
Insulin resistance
Medications
Nutritional causes
Vascular abnormalities
NOTE: Instead of labeling someone as a possible alcoholic or obese individual, I usually say this is due to a toxic/metabolic etiology to leave it up to clinical interpretation.
Steatosis:
Fatty liver, no signs of hepatitis
The degree of steatosis is measured using only the percentage MACROvesicular steatosis (Minimal = <5%, Mild = up to 30%, moderate = 30-60%, severe = >60%). NOTE: Microvesicular doesn’t count!
When you see steatosis, you need to assess for features of steatohepatitis! We usually can’t tell the difference histologically.
Steatohepatitis:
Steatosis (the degree/percentage does not matter, can have active steatohepatitis even if there is minimal steatosis).
Fibrosis is a feature needed for steatohepatitis, and occurs in a centrizonal (zone 3) pattern.
Ballooning hepatocyte degeneration.
Mallory-Denk body formation.
Zone 3 (centrizonal) sinusoidal/pericellular fibrosis-this can only be assessed with a trichrome stain.
NOTE: I like to see all of these features before I call steatohepatitis. I usually don’t give a degree of activity for these cases unless it is very mild .
Example Sign Out
FINAL DIAGNOSIS:
Liver, native, (core, wedge) biopsy:
Mild steatosis (20%) with active steatohepatitis.
Centrizonal sinusoidal and pericellular fibrosis.
See comment.
PATHOLOGIST'S COMMENT:The patient’s history of _ is noted. The specimen consists of an adequate core liver biopsy. The portal tracts contain minimal inflammation consisting primarily of lymphocytes. There is no significant interface activity. The interlobular bile ducts appear intact, without significant injury or inflammation. There is mild lobular inflammation. Mild steatosis (20%) is present with scattered ballooning hepatocyte degeneration with Mallory-Denk body formation. There is no significant cholestasis or hepatocyte dropout. A trichrome stain highlights centrizonal fibrosis with patchy sinusoidal and pericellular fibrosis. An iron stain is negative. A PAS-D stain is negative for PAS positive globules. Overall, these findings are consistent with mild steatosis with active steatohepatitis due a toxic/metabolic etiology.
If you wanted to go into more detail...
Steatohepatitis is a non-specific pattern of injury seen most commonly with morbid obesity, diabetes, insulin resistance, and alcohol abuse. It can be associated with nutritional causes, medications, various metabolic disorders and hepatic blood flow abnormalities (Kleiner DE, et al. Hepatology 41:1313-1321, 2005).)