Steatohepatitis

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Steatohepatitis is a fatty change of the liver (steaosis) with (histologic) evidence of liver injury. It can be due to a number of different causes.

Steatohepatitis
Diagnosis in short

Steatohepatitis. Trichrome stain.

LM steatosis (usually macrovesicular); hepatocyte injury -- ballooning degeneration (key feature), Mallory bodies; portal bridging (late stage)
Subtypes by etiology (classically): ASH, NASH -- all almost histologically identical
LM DDx steatosis, Wilson disease, hepatitis C, drug-induced liver disease
Gross pale/yellowish, often enlarged
Site liver - see medical liver disease

Associated Dx obesity, alcohol abuse
Prevalence common
Prognosis dependent on underlying cause
Treatment dependent on underlying cause

General

  • Steatohepatitis is a label for a set of histopathologic findings.
  • Fat accumulation (in hepatocytes) alone is liver steatosis.
    • It may be a pattern seen in drug toxicity, e.g. methotrexate toxicity.[1]

Etiology:

  1. Alcohol = alcoholic steatohepatitis (ASH).
  2. Not alcohol = non-alcoholic steatohepatitis (NASH).
  3. Drug/toxin.[2]

Notes:

  • Pathologists can comment on the etiology; however, the histomorphology is not distinctive. In other words, ASH and NASH are clinical diagnoses.
  • Steatohepatitis is a misnomer. It is not an -itis; inflammation is not the (predominant) pathologic process.

Microscopic

Features:

  • Steatosis (usually macrovesicular) - key feature.
    • If less than 10% ... consider alt. diagnosis/disease process.
  • Hepatocyte injury:
    • Ballooning degeneration - key feature (see introduction to liver).
    • Mallory bodies.
      • Mallory body wannabes: "occasional cytoplasmic clumping".
  • +/-Chicken-wire perisinusoidal fibrosis +/- zone III (centrilobular) fibrosis (early).
    • Late-stage disease - portal bridging.[3]

DDx:

Grading steatohepatitis

Grading inflammation:[4]

  • Grade 1 - steatosis, occasional ballooning degeneration, PMNs.
  • Grade 2 - obvious ballooning, obvious PMNs, chronic inflammation.
  • Grade 3 - panacinar steatosis.

Image

See also

References

  1. MG. 22 September 2009.
  2. Farrell, GC. (2002). "Drugs and steatohepatitis.". Semin Liver Dis 22 (2): 185-94. doi:10.1055/s-2002-30106. PMID 12016549.
  3. Gramlich, T.; Kleiner, DE.; McCullough, AJ.; Matteoni, CA.; Boparai, N.; Younossi, ZM. (Feb 2004). "Pathologic features associated with fibrosis in nonalcoholic fatty liver disease.". Hum Pathol 35 (2): 196-9. PMID 14991537.
  4. Nonalcoholic steatohepatitis: a proposal for grading and staging the histological lesions. Brunt EM, Janney CG, Di Bisceglie AM, Neuschwander-Tetri BA, Bacon BR. Am J Gastroenterol. 1999 Sep;94(9):2467-74. PMID 10484010.