Chronic Villitis

Abstract

An anatomical and metabolic interface between the mother and the fetus, villous placenta (placental disc) is of the utmost importance for the well-being of the fetus. In this context, chronic villitis leading to destruction of chorionic villi has robust clinical implications. The primary pathology of chronic villitis is the infiltration of chronic inflammatory cells (lymphocytes, plasma cells, and histiocytes) associated with destruction of the chorionic villi. A unique and scientifically important feature of chronic villitis is the fact that maternal lymphocytes are primary players of inflammation in the fetal chorionic villi in many occasions. Aetiologies of chronic villitis documented so far are infections by various organisms, yet it is evident that the most common form of chronic villitis, known as villitis of unknown aetiology, results from maternal immune responses against the fetus. This chapter will describe the pathological findings of representative examples of infectious chronic villitis and villitis of unknown aetiology.