Necrosis, a type of cell death resulting from disease, injury, or failure of the blood supply to an organ or tissue, was originally considered to be an accidental and unregulated cell death. Necrosis can be induced and proceed in a regulated manner like apoptosis, although in a caspase-independent manner.
Necroptosis arose from its unique characteristics combining apoptotic and necrotic features. Like apoptosis, necroptosis is carried out by a series of organized cellular components. As in necrosis, the ultimate stage of a necroptotic process is the swelling and rupture of the cell membrane, releasing damage-associated molecular patterns (DAMPs). Recently, a number of studies have provided new insights into the molecular regulation of necroptosis.
As I just did for another question, I suggest you take a look at the most recent account of cell death modes and mechanisms, just out. This might help you navigate through the multiple and often mixed cell death pathways that tend to coexist more often than not.
Cell Death Differ. 2018 Mar;25(3):486-541. doi: 10.1038/s41418-017-0012-4. Epub 2018 Jan 23.
Molecular mechanisms of cell death: recommendations of theNomenclatureCommittee on Cell Death 2018.