Correlation of ultrasound and pathologic findings of placental anomalies in pregnancies with elevated maternal serum alpha-fetoprotein.

Twenty pregnancies with elevated maternal serum alpha-fetoprotein (MSAFP), a normal fetus and unusual or abnormal placental/cord sonographic features are reported. These include: (A) gigantic enlargement with multiple sonolucent spaces of different size and shape (n = 2; Swiss cheese); (B) placental masses of variable echogenicity (n = 5); (C) cord masses with central echo-dense zone and peripheral hypoechoic areas (n = 2); (D) enlarged placentas with patchy decrease of echogenicity (n = 6; jelly-like); and (E) large sonolucent spaces with turbulent blood flow surrounded by normal placental tissue (n = 5; placental lakes). After delivery, these ultrasound features were compared with pathologic findings. Diffuse mesenchymal hyperplasia of the stem villi were found in the gigantic placentas (n = 2). The placental masses corresponded to chorioangiomas (n = 3), infarct (n = 1) or subamniotic hematoma (n = 1) and the cord masses to angiomyxomas (n = 2). The 'jelly-like' placentas were related to subchorial thrombosis (n = 2), massive fibrin deposition (n = 1) or hypertrophy with no obvious abnormalities (n = 3). Large subchorial thrombosis (n = 2), or no obvious abnormalities (n = 3) were observed in placentas with large lakes. These findings suggest that a large range of placental and cord anomalies are associated with elevated MSAFP and are potentially diagnosable by routine sonographic examination at the time of AFP screening.