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.
- 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
- 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
- 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)
- 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
- 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
- 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”)
We need your help! Pathology Student is completely ad-free.If you find us useful, please consider donating whatever feels right to you. Every bit helps!You can donate here.
- Kristine said Hi Rahwa – You’re correct: type I diabetes mellitus is mediated by a type IV hypersensit...
- Rahwa Haile said Hi! My classmates and I were given a case study where a 10 year old patient was diagnosed with Diabe...
- euis said such a good page! thank you so much
- wondimu amado said I Like It.
- wondimu amado said Thank you very much.because I Understand more about anaplasia.
- wondimu amado said Thank u.I Am second year public health student in Debre Markos University.I Am From Ethiopia.
- intel said very informative. Keep it up
- akhtar said Nice image…i answered a que in quiz after going through this…
- Kristine said Great!! Glad it was helpful
- Stephanie said Thank you so much! I’ve been fretting about which Robbins to get and this helps immensely! So...
- Sana Haq said Thank You for getting this concept cleared up!! I was spending the last hour struggling through this...
- narges said it is so useful.I undrestood Flexner-Wintersteiner Rosette well