Current Topics in Perinatal Pathology
Fetal Thrombotic Vasculopathy
Definition:
Fetal thrombotic vasculopathy (FTV) in the placenta is the presence of extensive avascular villi. This lesion usually is associated with demonstrable thrombi in the fetal circulation, either in the chorionic plate vessels, stem villous vessels or villous circulation. 1,2
Gross Description
Fetal Thrombotic Vasculopathy
Definition:
Fetal thrombotic vasculopathy (FTV) in the placenta is the presence of extensive avascular villi. This lesion usually is associated with demonstrable thrombi in the fetal circulation, either in the chorionic plate vessels, stem villous vessels or villous circulation.1,2
Gross Description
Distended fetal vessels can be seen on the placental surface. Older lesions tend to be white, firm, and easily palpable. Upon sectioning, the lumens of these blood vessels are distended with thrombus. Parenchyma supplied by these vessels is pale but spongy and soft. These areas are well defined. Older lesions are firmer in consistency.3,4
Figure 1
- Fetal blood vessels with occlusive thrombi
- Parenchyma composed of avascular villi
- Normal parenchyma
Microscopic Description
Mural or occlusive thrombi in fetal vessels are present. These can be superficial or deep. Some of the blood vessels can be completely obliterated (Figure 2). In some areas, extravasation of red blood cells into the vascular walls or calcifications can be seen (Figure 3). Main lesion consists of avascular and fibrotic chorionic villi (Figure 4a and 4b). Usually, a rim of prominent syncytial knots surrounds avascular villi. Small foci of FTV appear to be innocuous but if they involve more than 2.5% of the total placenta volume, there is an association with significant morbidity.
Figure 2
Figure 3
Figure 4a
Figure 4b
Clinical Associations and Differential Diagnosis
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Fetal – neonatal lesions
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Intrauterine growth restriction (IUGR)
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Low umbilical artery pH
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Neonatal hypoglycemia (maternal diabetes)
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Flow related disorders
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Fetal heart failure
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Visceral thromboemboli (renal veins)
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Cerebral infarcts
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Liver disease5
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Anatomical lesions
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Tight true knot of the umbilical cord
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Membraneous or velamentous vessels
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Long umbilical cord
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Endothelial injury
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Toxic exposure to meconium
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Acute inflammation (i.e. acute chorioamnionitis)
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Chronic villitis (i.e. CMV)
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Thrombophilia
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Hereditary deficiencies in coagulation inhbitors
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Maternal antiphospholipid antibodies
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Sepsis
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Table modified from [6].
References
1. Redline RW, Pappin A. Fetal thrombotic vasculopathy: the clinical significance of extensive avascular villi. Hum Pathol 1995;26:80-85.
2. Kraus FT, Acheen VI. Fetal thrombotic vasculopathy in the placenta: cerebral thrombi and infarcts, coagulopathies, and cerebral palsy. Hum Pathol 1999;30:759-769.
3. Kraus FT. Thrombosis of fetal stem vessels with fetal thrombotic vasculopathy and chronic villitis. Pediatr Pathol Lab Med 1996;16:143-148.
4. Hebisch G, Bernasconi MT, Gmuer J, Huch A, Stallmach T. Pregnancy associated recurrent hemolytic uremic syndrome with fetal thrombotic vasculopathy in the placenta. Am J Obstet Gynecol 2001;185:1265-1266.
5. Dahms BB, Boyd T, Redline RW. Severe perinatal liver disease associated with fetal thrombotic vasculopathy. Pediatr Dev Pathol 2002;5:80-85.
6. Modlin JF, Grant PE, Makar RS, Roberts DJ, Krishnamoorthy KS. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 25-2003. A newborn boy with petechiae and thrombocytopenia. N Engl J Med. 2003 Aug 14;349(7):691-700
