Q. I can’t seem to get the different types of necrosis straight (liquefactive, fibrinoid, etc.). Any help?
A. There are basically six distinct patterns of necrosis. It’s important to know about these, because they can give you a clue as to why the tissue died. We’ll go through these in bullet form to make it easy to compare.
Coagulative
- See this in infarcts in any tissue (except brain)
- Due to loss of blood
- Gross: tissue is firm
- Micro: Cell outlines are preserved (cells look ghostly), and everything looks red
Liquefactive
- See this in infections and, for some unknown reason, in brain infarcts
- Due to lots of neutrophils around releasing their toxic contents, “liquefying” the tissue
- Gross: tissue is liquidy and creamy yellow (pus)
- Micro: lots of neutrophils and cell debris
Caseous
- See this in tuberculosis
- Due to the body trying to wall off and kill the bug with macrophages
- Gross: White, soft, cheesy-looking (“caseous”) material
- Micro: fragmented cells and debris surrounded by a collar of lymphocytes and macrophages (granuloma)
Fat necrosis
- See this in acute pancreatitis
- Damaged cells release lipases, which split the triglyceride esters within fat cells
- Gross: chalky, white areas from the combination of the newly-formed free fatty acids with calcium (saponification)
- Micro: shadowy outlines of dead fat cells (see image above); sometimes there is a bluish cast from the calcium deposits, which are basophilic
Fibrinoid necrosis
- See this in immune reactions in vessels
- Complexes of antigens and antibodies (immune complexes) combine with fibrin
- Gross: changes too small to see grossly
- Micro: vessel walls are thickened and pinkish-red (called “fibrinoid” because it looks like fibrin but has other stuff in there too
Gangrenous necrosis
- See this when an entire limb loses blood supply and dies (usually the lower leg)
- This isn’t really a different kind of necrosis, but people use the term clinically so it’s worth knowing about
- Gross: skin looks black and dead; underlying tissue is in varying stages of decomposition
- Micro: initially there is coagulative necrosis from the loss of blood supply (this stage is called “dry gangrene”); if bacterial infection is superimposed, there is liquefactive necrosis (this stage is called “wet gangrene”)
Thanks! Made understanding the different types of necrosis and relevance of each, much easier!
I already love this site. Thank you so much for making it. I imagine this is an entry that tends to bring folks in, as it is so crucial in introducing Path. Quick, easy way to review what i am working on. Fantastic!
it was really understandable
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pathology student site is a very informative site for all medical students specifically for pathology students i like this site because i learn everyday new article about pathology.
Wonderful…………thanks Prof.
You’re welcome! Glad it was useful.
Brief and informative, i hope robbins can be written in this way too!
Robbins is written MUCH better than this!
I like the site provide nice summary ..
thank you for clear the type of necrosis .
I have some “necrosis” that i dont know which category should be..
1. the necrosis seen in solid tumor (“tumor” necrosis?)
2. the necrosis seen in cat-scratch disease, it’s little bit caseous looking but more palisaded cells aside…I think caseous is more likely a gross term?
Thanks for the brief and clear explanations .
summary is very nice
Thanks! Glad you found it useful.
I have fatty necrosis, and this info was very informative….Thanks
Very informative for a person that has these symptoms and the disease.
Great – Glad it helped! Hope you feel better.
cool, ws hlpful n esy to memorize
so perfect summary that what I need >>>>>
It is very excellent site to get advance knowledge of necrosis.
A very good summary that widen student’s memory 2 get more during reading. That is a very good work
Uuuhhh!!! So gud 2 b here. Itz brief n easier 4 d brain. . .provided av nt got liquefactive necrosis
What ‘s an excellent site. 10x.
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really so nice wounderfull side all informetion form this site so usenfull in daily practive hope i learn more form you if any training please i want to do
thanks
makes quick and easy mastery
Thank u so much..very nice info
wonderful