Necrosis (plural: necroses) is defined as unregulated cell death. This is in contrast to apoptosis, which is a form of regulated, or programmed, cell death .

Necrosis is the most common type of cell death observed in injury/disease. It occurs when cellular damage is so severe that lysosomal enzymes enter the cytoplasm, causing autodigestion of the cell .

The main types of necrosis are:

  • coagulative: tissue architecture is preserved 
  • liquefactive: loss of tissue architecture, formation of liquid/pus
  • caseous: most common with tuberculosis; friable, structureless cell debris
  • fat necrosis: refers to local areas of fat destruction, commonly encountered in pancreatitis