Necrosis is the death of body tissue. It occurs when too little blood flows to the tissue. This can be from injury, radiation, or chemicals. Necrosis cannot be reversed.
When large areas of tissue die due to a lack of blood supply, the condition is called gangrene.
Kumar V, Abbas AK, Aster JC. Cellular responses to stress and toxic insults: adaptation, injury, and death. In: Kumar V, Abbas AK, Aster JC, eds. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 2.