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Chronic chorioamnionitis: a clinicopathologic study of 17 cases
D J Gersell1, N J Phillips, K Beckerman
1Department of Pathology, Washington University School of Medicine, St. Louis, Missouri.
Abstract:
The clinicopathologic features of 17 cases of an unusual variant of chorioamnionitis distinguished by a pure or predominantly chronic inflammatory infiltrate in the fetal membranes rather than the usual acute inflammatory reaction are reported. In six cases, there was an equal (one case) or minor (five cases) component of acute inflammation in the fetal membranes as well. Concomitant villitis, found in 11 cases, was almost uniformly lymphohistiocytic and destructive, but it varied greatly in severity. Immunoperoxidase stains for cytomegalovirus, herpes simplex I and II, and Toxoplasma gondii; Warthin-Starry, Gomori methenamine silver, Dieterle, Gram and acid fast stains; placental or amniotic fluid culture; and limited maternal serologic studies failed to identify a specific infectious etiology in any case. Seven women had experienced at least one previous spontaneous abortion, fetal death in utero, or preterm birth. No patient reported a history of fever, rash, or flu-like syndrome during pregnancy. Serious antenatal complications were numerous. Preterm birth occurred in 13 cases. Gestational age ranged from 25 to 42 weeks (mean 32 weeks) and birth weight ranged from 740 to 3,230 g (mean 2,100 g). When expressed as a percentile for gestational age, 47% of infants had a birth weight at or below the 25th percentile, and 76% were at or below the 50th percentile. Two infants were born with gross anomalies, and one infant died in the neonatal period.
Insights
This study reports on a rare form of chorioamnionitis with chronic inflammation in fetal membranes. Infectious causes were not identified, and affected infants often experienced preterm birth and low birth weight.
Area of Science:
- Pathology
- Obstetrics
- Perinatology
Background:
- Chorioamnionitis is typically characterized by acute inflammation in the fetal membranes.
- An unusual variant presents with predominantly chronic inflammatory infiltrates.
Purpose of the Study:
- To describe the clinicopathologic features of this rare chorioamnionitis variant.
- To investigate potential infectious etiologies and clinical outcomes.
Main Methods:
- Case series analysis of 17 patients with chronic chorioamnionitis.
- Histopathologic examination of fetal membranes and placentas.
- Infectious workup including stains, cultures, and serology.
Main Results:
- 17 cases of chronic chorioamnionitis identified, with some cases showing mixed acute inflammation.
- Concomitant lymphohistiocytic villitis was frequent but variable in severity.
- No specific infectious agent was identified despite extensive testing.
- High rates of preterm birth (13/17), low birth weight (76% ≤50th percentile), and adverse neonatal outcomes were observed.
Conclusions:
- This chronic inflammatory pattern of chorioamnionitis is distinct from the typical acute form.
- The etiology remains elusive, suggesting non-infectious or unidentified infectious agents.
- This condition is associated with significant adverse pregnancy outcomes, including preterm birth and fetal growth restriction.