Definition: Abscesses are localized collections of purulent inflammatory tissue caused by suppuration buried in a tissue, an organ, or a confined space. They are produced by deep seeding of pyogenic bacteria into a tissue.

 Abscesses have a central region that appears as a mass of necrotic leukocytes and tissue cells. There is usually a zone of preserved neutrophils around this necrotic focus, and outside this region vascular dilation and parenchymal and fibroblastic proliferation occur, indicating the beginning of repair.

 In time, the abscess may become walled off and ultimately replaced by connective tissue.

Localization

 cerebral abcess
 pulmonary abcess
 cutaneous abcess
 renal abcess