* Prenatal diagnosis and obstetrical US Service. Obstetrics and Gynecology Department. Montebelluna Hospital. Treviso, Italy.
** Ultrasound Division, ASL Roma B, Rome, Italy.
Introduction
The chorioangioma is the most common benign tumor of the placenta. The diagnosis can be made by ultrasound. Chorioangioma as defined as a circumscribed round mass, mostly hypoechoic, located near the chorial plate and the umbilical cord insertion. As they grow, chorioangiomas protrude into the amniotic cavity. Color Doppler can demonstrate the vascularization within the tumor.
Chorioangiomas, especially the large ones, are frequently associated with polyhydramnios and other complications such as preterm delivery, fetal anemia and congestive cardiac heart failure. Less commonly, they can be associated with intrauterine growth restriction, thrombocytopenia and placenta previa. It has been postulated that polyhydramnios is a result of a transudation of fluid through the walls of the blood vessels of the tumor, and then through the chorial plate of the placenta into the amniotic cavity. Most authors think that polyhydramnios occurs mainly in cases with placental cord insertion close to the chorioangioma. In the past, only chorioangiomas bigger than 5 centimeters were considered large enough to produce fetal complications. More recently, it has been determined that the vascularity of a tumor, rather than it's size, determines the likelihood of fetal complications.
When chorioangioma is not directly involved in the fetal circulation, the umbilical artery Doppler is normal. In case if a fistula between fetal circulation and tumor vessels, fetal complications can occur. A significant change in the Doppler flow velocity waveform is verified with loss of end diastolic velocity in the tumor and in the central arterial circulation. In case there is a low or absent diastolic flow in the umbilical artery, the examination of the heart and arterial and venous fetal vessels, will help in the evaluation of the fetal circulation.
Case report
A 30-year-old patient, G2P1 with non-contributive personal or family history was referred to our department at 23 weeks of gestation for an enlarged amount of the amniotic fluid and placental mass. These findings were detected during the second trimester ultrasound scan performed in a different center.
Polyhydramnios (AFI 32 cm, maximum vertical pocket of 10 cm) and the presence of the tumor of the fetal surface of placenta were seen while performing our ultrasound scan. Tumor measured 80 x 44 mm and was protruding into the amniotic cavity. The tumor was hypoechoic with increased vascularization detected by Doppler flow. Tumor was located 29 mm from placental insertion of the umbilical cord.
No fetal anomalies were detected. There were no signs of fetal anemia; no cardiomegaly (normal 4 - chamber view), no tricuspid regurgitation and no pericardial effusion or subcutaneous edema.
Two successful decompress amniocentesis were performed at 25 and 28 weeks. Peak systolic velocity of middle cerebral artery was measured every ten days for prediction of the fetal anemia. All the measurement were within the normal limits, according to Mari curves.
At 32 weeks of gestation the patient was transferred to a tertiary center. Fetal growth was stagnating and there was a high resistance index during the umbilical artery Doppler measurement at 33 weeks. Corticosteroids for lung maturity induction were administered to the mother. At 34 weeks, a baby of 2300 grams with Apgar score 8/9 at 1st/5th minute, was delivered spontaneously. Neonate was dismissed 5 days after delivery in an excellent condition.
The pathology examination of the placenta confirmed the placental tumor - chorioangioma.
Images 1,2: Images show a tumor of the placenta, chorioangioma, it's size is 80 x 40 mm.