Necrosis can be described as a pathological process of cell death which could have been resulted from infections, hypoxia, trauma or toxins. Unlike apoptosis, necrosis is uncontrolled and release lots of chemicals from the dying cell to which causes damage to surrounding cells. Inflammation is often initiated due to necrosis.

Sometimes fat necrosis only shows up on a screening mammogram. Fat necrosis almost always occurs as an after effect of surgery of the breast. In the minority of cases the necrotic mass comes from trauma, like a punch or knock to the breast. Fat necrosis may also develop following radiation treatments.

Progressive outer retinal necrosis was identified in the early 1990s, thereby classifying an ‘atypical acute retinal necrosis’, necrotising herpetic retinopathies being excluded by the AVS criteria. 1, 3, 6, 8 Cytomegalovirus was first isolated in 1957; however, the earliest descriptions of cytomegaloviral retinitis were in the early 1970s.