We talk about necrosis and we all know it’s bad. Even those of us who aren’t in medicine use the term. Normally, we just apply it to any sort of cell death and deterioration, but there are actually 6 different types! They are all essentially based on the cause of cell death. For med students, it’s important to understand the difference and when we’re going to see which. Below is a listing of those 6 types and a little bit of information about them. Also, be sure to read the paragraph at the end!
Coagulative
Seen in all tissue (except brain)
Due to loss of blood
Gross: Tissue is firm
Micro: Cell outlines are preserved (ghostly look) but no nuceli. Everything looks red
Liequefactive
Seen in infections and brain infarcts
Due to lots of neutrophils around releasing toxic contents which liquefies the tissue
Gross: tissue is liquidy and creamy yellow (from the pus formation)
Micro: Lots of neutrophils and cell debris.
Caseous
Uniquely seen in tuberculosis
Due to body trying to wall off and kill infection with macrophages
Gross: White, soft, cheesy-looking material
Micro: Fragmented cell and debris surrounded by a collar of lymphocytes and macrophages
Fat
Acute inflammation affecting tissues with lots of fat (i.e. pancreas and breast tissue)
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: Anucleated adipocytes with deposits of calcium
Fibrous
Seen in immune reactions in vessels
Immune complexes and fibrin are deposited in vessel walls
Gross: changes too small to see grossly
Micro: vessel walls are thickened and pinkish-red
Gangrenous
See when an entire limb loses blood supply and dies (usually lower leg)
Not actually a kind of necrosis
Gross: Skin looks black and dead, varying stages of decomposition
Micro: Initially, coagulative from loss of blood supply (“dry gangrene”). If includes bacterial infection, liquefactive necrosis (“wet gangrene”).
Also, I want to be sure that it’s clear that this is essentially a repost of the article below. When looking for some base information to easily explain the differences in types of necrosis, I found this article. It was so incredibly helpful that I couldn’t think of any other damn way of presenting the information! I did make a few minor adjustments/rewordings – just some things I thought weren’t entirely clear or lacked a little bit of detail. However, it was so clear and concise already, so I didn’t have to do much!