CD42b immunostaining as a marker for placental fibrinoid in normal pregnancy and complications

Abstract

BackgroundThere are two types of the fibrinoid deposits within the placenta, and the nature of these fibrinoid are poorly understood in clinical setting. DesignFibrinoid deposits within normal pregnancy and the pregnancy related complications are studied using the routine hematoxylin and eosin stain and immunostaining for CD42b as a marker for platelet aggregates and fibrin. ResultsFibrin-like fibrinoid is associated with platelet aggregates characterized by the positive immunostaining for CD42b and coagulatory cascade activation with blood flow changes in the circulation and intervillous spaces. Matrix-type fibrinoid is not associated with platelet aggregates and coagulation and its pathogenesis is unknown. ConclusionFibrinoid deposits within the intervillous spaces are mostly from maternal circulation and these fibrinoids are likely the result of the laminar blood flow change at specific anatomic locations, leading to activation of coagulatory cascade. The pathogenesis of matrix-like fibrinoid is unclear. CD42b immunostaining is helpful in difficult cases.