Photomicrograph of the tissue around an abscess, showing proliferating fibroblasts. Normally, scarring in the CNS is by astrocyte proliferation.
Abscess is one of two disorders in which fibroblasts proliferate to form scar.
The other is intracerebral hemorrhage. The iamge also contains proliferating, reactive astrocytes and a few lymphocytes and macrophages. An abscess arises from septic emboli or direct exposure of the brain to outside organisms through head trauma or erosion of an infection through the bone as in sinusitis and mastoiditis. Both bacteria and fungi can cause abscesses. In parenchymal abscesses, an area of microvascular damage due to a septic embolus causes a small area of necrosis due to the influx of neutrophils and bacteria or fungi into the area.