Address correspondence to Harold Schulman MD, Department Obstetrics/Gynecology, Winthrop University Hospital, 259 First Street, Mineola, NY 11501-3987. Ph: 516-663-2264, Fax: 516 742-7821

Synonyms: Hamartoma, hemangioma, endothelioma, fibroma, fibro-, myxo-, and angio­sarcoma.

Definition: A placental tumor composed of vascular spaces.

Etiology: It has been postulated that these tumors begin around the 16^th-17^th day of development when a newly formed angioblastic mass becomes isolated from the rest of the proliferating tropho­blast.

Histology: Microscopically the tumor is benign and has been classified into three types: cellular or young, vascular or adult, and the degenerative type.

Prevalence: Careful pathologic examination of the placenta reveals that the prevalence of chorio­angio­mas may be 1%.

Pathogenesis: Unknown.

Differential diagnosis: Placental lake or thrombus, retrochorionic hemorrhage.

Prognosis: Depends upon involvement with umbilical circulation, and may depend upon size.

Recurrence risk: None.

Management: Depends upon involvement of umbilical circulation.

Mesh Placenta: tumor ICD9 762.2 CDC 762.200

Introduction

Since the placenta is an organ composed of blood vessels, it is not surprising that its primary neoplasm would be a vascular tumor. This tumor may be lethal for the fetus, because it may act as a multichanneled fistula that results in fetal microangiopathic anemia, transplacental hemorrhagic anemia, and heart failure.

Case report

A 27-year-old P₀ had a routine ultrasound examination at 20 weeks gestation, and a placental chorioangioma was noted (fig. 1). The fetus was average for gestational age, and the amniotic fluid volume was normal. The umbilical cord insertion was adjacent to the tumor. Dopplers from the umbilical artery and intraplacental vessels were normal. Follow-up ultrasounds and Dopplers done on two occasions confirmed continued fetal growth and normal umbilical flow velocity. The patient went into labor at 38 weeks gestation. The active phase of labor was dysfunctional and did not respond to oxytocin. A low transverse cervical cesarean section was done yielding a healthy normal female weighing 2900g. The placenta weighed 730g and contained a 97 by 85 by 42 mm tumor off the fetal surface (fig. 1,bottom). The histology of the tumor was characteristic of a vascular chorio­angioma (fig. 1, insert). The mother and baby did well. She is currently pregnant again with a normal placentation.

Figure 1: The gray-scale and pulsed wave Doppler and the specimen. Insert: the vascular channels

Discussion

Diagnosis

Chorioangiomas are usually solitary tumors that range from 5 to more than 200 mm. Their shape is usually spherical but may be multilobulated. They typically grow beneath the fetal surface of the placenta but also may appear at the maternal surface. The diagnosis is generally made by ultrasound. It is usually an incidental finding. A smooth echogenic ovoid mass is seen protruding into the amniotic cavity and has a different echodensity than the remainder of the placenta. The site of placental insertion of the umbilical cord should be sought. Color flow mapping should be done, and all vessels should have Doppler analysis to assess the presence of diastolic flow⁷. When the placenta is delivered, the tumor (being vascular) has a characteristic red blue color and is well demarcated.

Pathophysiology

The widespread usage of ultrasound has allowed early diagnosis of chorioangiomas and a better understanding of its potential consequences. Both fetal and maternal complications may arise. Early in pregnancy the tumor may be a weak link in placental integrity and may first be detected when there is an elevated maternal serum aFP^1. Later in pregnancy, this leakage may result in maternal thrombocytopenia that could be an autoimmune response or a reaction to tumor necrosis and embolism^2. If there is direct communication between the fetal circulation and the tumor, there may be catastrophic consequences. Since the vascular spaces provide a maze-like pathway with minimal surrounding connective tissue, there may be turbulence, resulting in red cell injury and vessel wall rupture. The turbulence leads to a micro­angio­pathic anemia. Vessel rupture could produce fetal maternal hemorrhage and fetal anemia, but it also could result in fibrosis and sealing of the fistula^3-5.

A fistula between an artery and vein results in short-circuiting of blood from a high to a low resistance vascular bed. Lowered peripheral resistance stimulates increased cardiac output and heart rate. There is a significant fall in diastolic blood pressure. This alone can lead to a high output cardiac failure. If an anemia is added to this process, the likelihood for failure increases. Heart failure in the fetus can be suspected when there is hydrops, cardiac dilatation, and increased regurgitation manifested in the tricuspid area, an enlarged “a” wave of the inferior vena cava, and pulsations in the umbilical vein.

There is one reported case in which there was fetal hydrops and recovery, allegedly associated with necrosis of the tumor⁶. There is no data about the effect of the tumor on the course of labor.

Doppler

When the fetal circulation is involved in the fistula, there is usually a significant change in the Doppler flow velocity waveform. In the normal fetal circulation (by 20 weeks gestation), there is a large amount of diastolic flow at end diastole. With the aid of color flow, secondary and tertiary branches of the umbilical artery can be seen in the interior of the placenta. These vessels usually show lower resistance than the larger branches of the umbilical artery. When the chorioangioma is not directly involved in the fetal circulation, the umbilical vessels give off normal flow velocity signals. When there is a fistulous communication, there is a loss of end diastolic velocity in the tumor and in the central arterial circulation. The loss of end diastolic flow implies a significant alteration of flow dynamics. In this circumstance we could postulate a combination of events, such as reduced cardiac output, heart failure, anemia, and the reduced resistance caused by the fistula.

Management

First decide whether the tumor is intimately involved in the fetal circulation. Doppler examination of the umbilical circulation will give a quick answer. If the umbilical flow velocity is normal, the tumor is probably independent and of no consequence. One or two repeat examinations at monthly intervals may be useful to confirm these findings. If the umbilical flow velocity wave form is abnormal (eg, reduced or no diastolic flow), color flow mapping may be useful to further study the tumor hemodynamics. When there are abnormalities of umbilical flow, an examination of the heart, aorta, middle cerebral artery, and vena cava will help in the evaluation of the functional state of the fetal circulation. If there is hydrops or fetal heart failure, a medical emergency exists. The condition of the fetus will determine the therapeutic potentials available. If the fetus is hydropic it may benefit from a transfusion⁸. Cordocentesis would be necessary to confirm the presence of anemia. Ultimate cure in the immature fetus could be achieved by obliteration of the fistula. With the aid of color flow mapping, the tumor could be embolized with clotted blood. These therapeutic approaches are speculative and not yet documented.

References

1. Jauniaux E, Moscoso G, Campbell S. et al.: Correlation of US and pathologic findings of placental anomalies in pregnancies with elevated MSAFP. Eur J Obstet Gynecol Reprod Med 37:219-30, 1990.

2. Limaye NS, Tchabo JG. Asymptomatic thrombocytopenia associated with chorioangioma of placenta. Am J Obstet Gynecol 161:76-7 1989.

3. Bauer GR, Fojaco RM, Boncalari E. et al: Microangiopathic hemolytic anemia and thrombocytopenia in a neonate associated with a large placental chorioangioma. Pediatrics 62:574-7 1978.

4. Brandt CA, Ryom C, Grove A. Chorioangioma placentae and feto-maternal transfusion; a report of 2 cases. Eur J Obstet Gynecol Reprod Biol 33:95-8 1989.

5. Eldar-Geva T, Hochner-Celnikier D et al.: Fetal high output cardiac failure and acute hydramnios caused by large placental chorioangioma. Case report. Br J Obstet Gynecol 95:1200-3, 1985.

6. Chazotte C, Girz B, Koenigsberg M, Cohen W. Spontaneous infarction of placental chorioangioma and associated regression of hydrops fetalis. Am J Obstet Gynecol 163:11180-1, 1990.

7. Gitsch G, Deutinger J, Bernaschek G.: Prenatal diagnosis of placental tumor using Doppler sonography. Geburtshilfe Frauerheilkd 50:986-8, 1990.

8. Hirata GI, Masaki DI, O"Toole M et al.: The use of color flow mapping and Doppler velocimetry in the diagnosis and management of a placental chorioangioma associated with non-immune fetal hydrops. Am J Obstet Gynecol. (in press).