Fibrinoid necrosis is a specific type of tissue damage characterized by the buildup of fibrin-like material in tissues, especially within blood vessel walls. It usually occurs when blood vessels become severely injured due to immune reactions or high blood pressure. The name “fibrinoid” comes from its similarity to fibrin, a protein normally involved in blood clotting.
Fibrinoid necrosis typically occurs in response to specific types of injury or inflammation.
Common causes include:
Under a microscope, fibrinoid necrosis appears as bright pink, structureless deposits within or around blood vessel walls. These deposits contain fibrin, plasma proteins, and cellular debris, resulting in the affected area having a distinctive, smooth, and amorphous appearance. Pathologists use special stains, such as hematoxylin and eosin (H&E), to highlight the fibrinoid material, making it easier to see clearly against normal surrounding tissues.
Fibrinoid necrosis weakens blood vessel walls, which can lead to serious complications like bleeding (hemorrhage) or blood clots (thrombosis). These complications can disrupt blood flow and damage organs, affecting their ability to function properly. Identifying fibrinoid necrosis helps pathologists diagnose certain conditions, understand the severity of the disease, and guide appropriate treatments.