Difference between revisions of "Steatosis"

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#redirect [[Liver_pathology#Steatosis_of_the_liver]]
'''Steatosis''' is a fatty change in the liver associated with a number of underlying causes.
 
It is also known as '''fatty liver'''.
 
==General==
===Classification===
Can be divided into:
#Macrovesicular steatosis.
#*Common.
#Microvesicular steatosis.
#*Rare.
#*Potentially life threatening.<ref name=pmid15503661>{{Cite journal  | last1 = Jolly | first1 = RA. | last2 = Ciurlionis | first2 = R. | last3 = Morfitt | first3 = D. | last4 = Helgren | first4 = M. | last5 = Patterson | first5 = R. | last6 = Ulrich | first6 = RG. | last7 = Waring | first7 = JF. | title = Microvesicular steatosis induced by a short chain fatty acid: effects on mitochondrial function and correlation with gene expression. | journal = Toxicol Pathol | volume = 32 Suppl 2 | issue =  | pages = 19-25 | month =  | year =  | doi =  | PMID = 15503661 | URL = http://tpx.sagepub.com/cgi/pmidlookup?view=long&pmid=15503661 }}</ref>
 
Note:
*It is considered technically incorrect to say the liver, in steatosis/steatohepatitis, contains ''adipocytes''; they are ''lipid-laden hepatocytes'',<ref>Guindi, M. September 2009.</ref> despite that:
**Histologically, these cells look like adipocytes.
**Lipid-laden hepatocytes have gene activations suggestive of adipogenic-like transformation.<ref>URL: [http://www.jci.org/articles/view/20513/version/1 http://www.jci.org/articles/view/20513/version/1]. Accessed on: 23 September 2009.</ref>
 
===Etiology===
====Microvesicular steatosis====
Microvesicular steatosis DDx:<ref name=pmid2177300>{{cite journal |author=Hautekeete ML, Degott C, Benhamou JP |title=Microvesicular steatosis of the liver |journal=Acta Clin Belg |volume=45 |issue=5 |pages=311–26 |year=1990 |pmid=2177300 |doi= |url=}}</ref>
*Acute fatty liver of pregnancy,
*Reye's syndrome.
*Drug toxicity:
**Sodium valproate toxicity.
**High-dose tetracycline toxicity.
*Jamaican vomiting sickness.
*Congenital defects of urea cycle enzymes.
 
Less common causes:
*[[Alcoholism]].
*Hepatitis D.
*Weird stuff:
**Congenital defects of fatty acid beta oxidation,
**Cholesterol ester storage disease,
**Wolman disease and Alpers syndrome.
 
The classic causes of microvesicular steatosis are:<ref>[http://www.mailman.srv.ualberta.ca/pipermail/patho-l/1996-June/001788.html http://www.mailman.srv.ualberta.ca/pipermail/patho-l/1996-June/001788.html]</ref>
*Fatty liver of pregnancy.
*Aspirin (Reye's syndrome).
*Tetracycline.
It was once thought that all other causes of fatty liver produce macrovesicular steatosis.
 
====Macrovesicular steatosis====
Can sometimes be divided into ''centrilobular'' predominant and ''periportal'' predominant.<ref name=pcddx_steatosis>Steatosis. pathconsultddx.com. URL: [http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970840-3 http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970840-3]. Accessed on: 2 Sep 2009.</ref>
 
Centrilobular predominant (zone III) - ''DOA'':<ref name=pcddx_steatosis/>
*[[Diabetes mellitus]].
*Obesity, non-alcoholic steatohepatitis (NASH).
*Alcoholic liver disease, alcoholic steatohepatitis (ASH).
 
Periportal predominant (zone I) - ''TAPES'':<ref name=pcddx_steatosis/>
*Total parenteral nutrition (TPN).
*[[AIDS]].
*Phosphorus poisoning.
*Exogenous steroids.
*[[Starvation]].<ref name=pmid10600264>{{Cite journal  | last1 = Nagy | first1 = I. | last2 = Németh | first2 = J. | last3 = Lászik | first3 = Z. | title = Effect of L-aminocarnitine, an inhibitor of mitochondrial fatty acid oxidation, on the exocrine pancreas and liver in fasted rats. | journal = Pharmacol Res | volume = 41 | issue = 1 | pages = 9-17 | month = Jan | year = 2000 | doi = 10.1006/phrs.1999.0565 | PMID = 10600264 }}</ref>
 
Notes:
*[[HCV]] genotype 3 is reported to cause periportal steatosis.<ref name=pmid16614743>Yoon EJ, Hu KQ. Hepatitis C virus (HCV) infection and hepatic steatosis. Int J Med Sci. 2006;3(2):53-6. Epub 2006 Apr 1. PMID 16614743. Avialable at: [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1415843 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1415843]. Accessed on: September 9, 2009.</ref>
*Donor livers with more ''macrovescicular steatosis'' = worse outcome.
**More than 30% means the liver is undesirable for [[Liver transplantation pathology|transplantation]].<ref>STC. 6 December 2010.</ref>
 
==Microscopic==
Features - macrovesicular steatosis.
*One large vacuoles - similar to mature adipose tissue.
*Nucleus is eccentric.
 
Features - microvesicular steatosis.
*Multiple small (clear) cytoplasmic vacuoles - similar to brown fat, as seen in a [[hibernoma]].
*Nucleus is central.<ref>STC. 6 December 2010.</ref>
 
===Grading===
Quantity of fat is usually given as a percentage and graded ''mild'', ''moderate'', or ''marked''.
*Mild <33%, moderate >33% & <66%, marked >66%.<ref>Guindi, M. September 17, 2009.</ref>
 
===Images===
<gallery>
Image:Periportal_hepatosteatosis_intermed_mag.jpg | Periportal steatosis. (WC/Nephron)
</gallery>
Image:
<gallery>
Image:Non-alcoholic_fatty_liver_disease1.jpg | Centrilobular steatosis. (WC/Nephron)
</gallery>
 
==See also==
*[[Steatohepatitis]].
 
==References==
{{Reflist|2}}


[[Category:Diagnosis]]
[[Category:Diagnosis]]
[[Category:Liver pathology]]

Revision as of 03:12, 4 January 2016

Steatosis is a fatty change in the liver associated with a number of underlying causes.

It is also known as fatty liver.

General

Classification

Can be divided into:

  1. Macrovesicular steatosis.
    • Common.
  2. Microvesicular steatosis.
    • Rare.
    • Potentially life threatening.[1]

Note:

  • It is considered technically incorrect to say the liver, in steatosis/steatohepatitis, contains adipocytes; they are lipid-laden hepatocytes,[2] despite that:
    • Histologically, these cells look like adipocytes.
    • Lipid-laden hepatocytes have gene activations suggestive of adipogenic-like transformation.[3]

Etiology

Microvesicular steatosis

Microvesicular steatosis DDx:[4]

  • Acute fatty liver of pregnancy,
  • Reye's syndrome.
  • Drug toxicity:
    • Sodium valproate toxicity.
    • High-dose tetracycline toxicity.
  • Jamaican vomiting sickness.
  • Congenital defects of urea cycle enzymes.

Less common causes:

  • Alcoholism.
  • Hepatitis D.
  • Weird stuff:
    • Congenital defects of fatty acid beta oxidation,
    • Cholesterol ester storage disease,
    • Wolman disease and Alpers syndrome.

The classic causes of microvesicular steatosis are:[5]

  • Fatty liver of pregnancy.
  • Aspirin (Reye's syndrome).
  • Tetracycline.

It was once thought that all other causes of fatty liver produce macrovesicular steatosis.

Macrovesicular steatosis

Can sometimes be divided into centrilobular predominant and periportal predominant.[6]

Centrilobular predominant (zone III) - DOA:[6]

  • Diabetes mellitus.
  • Obesity, non-alcoholic steatohepatitis (NASH).
  • Alcoholic liver disease, alcoholic steatohepatitis (ASH).

Periportal predominant (zone I) - TAPES:[6]

  • Total parenteral nutrition (TPN).
  • AIDS.
  • Phosphorus poisoning.
  • Exogenous steroids.
  • Starvation.[7]

Notes:

  • HCV genotype 3 is reported to cause periportal steatosis.[8]
  • Donor livers with more macrovescicular steatosis = worse outcome.

Microscopic

Features - macrovesicular steatosis.

  • One large vacuoles - similar to mature adipose tissue.
  • Nucleus is eccentric.

Features - microvesicular steatosis.

  • Multiple small (clear) cytoplasmic vacuoles - similar to brown fat, as seen in a hibernoma.
  • Nucleus is central.[10]

Grading

Quantity of fat is usually given as a percentage and graded mild, moderate, or marked.

  • Mild <33%, moderate >33% & <66%, marked >66%.[11]

Images

  • Periportal steatosis. (WC/Nephron)

Image:

  • Centrilobular steatosis. (WC/Nephron)

See also

References

  1. ↑ Jolly, RA.; Ciurlionis, R.; Morfitt, D.; Helgren, M.; Patterson, R.; Ulrich, RG.; Waring, JF.. "Microvesicular steatosis induced by a short chain fatty acid: effects on mitochondrial function and correlation with gene expression.". Toxicol Pathol 32 Suppl 2: 19-25. PMID 15503661.
  2. ↑ Guindi, M. September 2009.
  3. ↑ URL: http://www.jci.org/articles/view/20513/version/1. Accessed on: 23 September 2009.
  4. ↑ Hautekeete ML, Degott C, Benhamou JP (1990). "Microvesicular steatosis of the liver". Acta Clin Belg 45 (5): 311–26. PMID 2177300.
  5. ↑ http://www.mailman.srv.ualberta.ca/pipermail/patho-l/1996-June/001788.html
  6. ↑ 6.0 6.1 6.2 Steatosis. pathconsultddx.com. URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970840-3. Accessed on: 2 Sep 2009.
  7. ↑ Nagy, I.; Németh, J.; Lászik, Z. (Jan 2000). "Effect of L-aminocarnitine, an inhibitor of mitochondrial fatty acid oxidation, on the exocrine pancreas and liver in fasted rats.". Pharmacol Res 41 (1): 9-17. doi:10.1006/phrs.1999.0565. PMID 10600264.
  8. ↑ Yoon EJ, Hu KQ. Hepatitis C virus (HCV) infection and hepatic steatosis. Int J Med Sci. 2006;3(2):53-6. Epub 2006 Apr 1. PMID 16614743. Avialable at: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1415843. Accessed on: September 9, 2009.
  9. ↑ STC. 6 December 2010.
  10. ↑ STC. 6 December 2010.
  11. ↑ Guindi, M. September 17, 2009.
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