Coagulative versus liquefactive necrosis
Coagulative necrosis (the dead cells' proteins set, so their shape stays) keeps ghost-like outlines, whereas liquefactive necrosis (the tissue melts to a liquid, so its shape goes) loses all structure.
Remember
After a loss of blood supply, a solid organ such as the liver usually shows coagulative necrosis with ghost outlines, whereas the brain, the main exception, shows liquefactive necrosis with only debris left.
Memory aid
soft brain turns to liquid, whereas solid organs such as the liver keep their shape like a cooked egg white
Use the picture of a soft brain turning to liquid and a solid organ such as the liver keeping its shape like cooked egg white.
Necrosis is the change in appearance of tissue once its cells have died, and microscopic changes take several hours to become visible.
Coagulative necrosis is what ischaemia (too little blood supply) usually gives in a solid organ, for example the liver, kidney or heart. Proteins in the dead cells are denatured (their folded shape is lost, so they clump and set, as egg white does when cooked). Because of this, enzymes digest the cells only slowly. The outlines of the cells and the framework of the tissue therefore stay in place for several days. Under the microscope you see pale, ghost-like outlines of cells that have no nuclei. An infarct is an area of tissue that has died because of loss of its blood supply.
Liquefactive necrosis is the opposite, because enzymes digest the dead tissue into a soft, liquid mass. No cells can be recognised under the microscope, only debris. It occurs in loose, soft tissue such as the brain and in abscesses (collections of pus). It also develops in bacterial infections, where enzymes from neutrophils digest the tissue. The brain is the main exception, because its ischaemic necrosis is liquefactive. It is not fully understood why the brain liquefies after ischaemia.
Caseous necrosis looks cheese-like, mixes the two patterns and is classically seen in tuberculosis. Fat necrosis happens in fat-rich tissue such as the pancreas and breast, where lipase (a fat-digesting enzyme) releases fatty acids that bind calcium to form chalky white soaps.
Key facts
- Coagulative necrosis
- the usual pattern after ischaemia in solid organs such as the liver, kidney and heart.
- Coagulative appearance
- pale, ghost-like outlines of cells without nuclei, with the tissue framework preserved.
- Coagulative mechanism
- denatured proteins coagulate, so the dead cells are digested only slowly.
- Liquefactive necrosis
- enzymes digest the dead tissue into a liquid mass of debris, with no cell outlines left.
- Liquefactive sites
- the brain after ischaemia, and abscesses (collections of pus).
- Timing
- coagulative necrosis keeps the tissue framework for several days, but liquefactive necrosis loses it.
Exam traps
- Coagulative necrosis is not the pattern of an ischaemic infarct of the brain, because dead brain tissue is digested into debris instead of keeping its outline.
- Liquefactive necrosis does not leave ghost outlines in a solid organ, because it digests the dead tissue into a liquid mass with no cell outlines left.
- Fat necrosis is not the general response of a solid organ to ischaemia, because it is destruction of fat by lipase in tissue with many fat cells, such as the pancreas and breast.
Read the full notes
Tested in 6 SimpleMed+ questions
Practice it in Pathology, with the answer and a full explanation after every question.
Practice these questions