Fibrinoidinen

Fibrinoidinen is a term found in some language contexts to denote fibrinoid-like substances or deposits, particularly in pathology. In English-language medical literature, the more common terms are fibrinoid material and fibrinoid necrosis. When used, fibrinoidinen generally refers to amorphous, eosinophilic deposits that resemble fibrin and arise from immune- and injury-driven processes in tissues.

Histologically, fibrinoidinen appear as homogeneous, acellular, and often finely granular areas within the extracellular matrix. They are typically rich in fibrin, immune complexes, and complement, and may involve basement membrane components. Staining characteristics on routine light microscopy can vary but often show a bright pink or eosinophilic appearance on hematoxylin-eosin slides, with potential periodic acid–Schiff positivity depending on associated materials.

Fibrinoidinen are most commonly observed in conditions featuring immune-mediated vascular injury. Examples include fibrinoid necrosis of arterial walls in polyarteritis nodosa and related vasculitides, immune complex–mediated glomerulonephritis, and placental or decidual vessels in obstetric complications such as preeclampsia. They can also accompany malignant hypertension and other states causing severe vessel wall damage.

Pathogenesis typically involves leakage of plasma proteins into vessel walls, deposition of immune complexes, and activation of the complement system, leading to structural destruction and eosinophilic, fibrin-rich deposits. Clinically, the presence of fibrinoidinen on histology signals significant vascular injury and guides differential diagnosis and management in systemic inflammatory or hypertensive diseases.

See also: fibrinoid necrosis, vasculitis, immune complex deposition, glomerulonephritis.