• The large villus on the right is involved by villitis
• The villus on the left is normal.
• Note the inflamed villus has no identifiable circulation.
• The inflammatory cels are lymphoctyes and macrophages.
• Approximately 5% associated with viral infections such as CMV or parvovirus B19, listeria or other organisms
• Vast majority are non-specific or of unknown etiology
• In cases caused by organisms the infection reaches the placenta via the maternal circulation
• The organisms breach the villi and involve the stroma with a fetal inflammatory response
• In non-specific villitis the cells first accumulate in the intervillous space ("intervillositis") and then cross into the villus stroma
• These cells are maternal CD3+ T cells.
• Other studies suggest that cells within the villus may be either fetal or maternal in origin.
• Between 5-10% of consecutive pregnancies
• Recurrent if not infectious
• Associated with intrauterine growth retardation and poor pregnancy outcome
• Recurrent (non-infectious variety)
• Associated with intrauterine growth retardation
• May also be associated with pregnancy induced hypertension
|General Gross Description|
• May have pale granular appearance to villi
• Usually normal
|General Micro Description|
• Mononuclear inflammation in the intervillus space
• Erosion of the trophoblast and trophoblast necrosis resulting in an irregular villus outline
• Agglutination of the villi
• Mononuclear inflammation within the villus stroma
• Plasma cells and lymphocytes as well as inclusions may be seen in viral infections
• Eventual destruction of the fetal circulation with hemosiderin deposition
• End result is avascular villus
• Benirschke K, Kaufmann P. Pathology of the human placenta, 3rd ed. New York: Springer-Verlag, 1995, pp. 596-601.