Background
While hemangioma of the placenta is sometimes seen, hemangioma of the umbilical cord is very rare. The clinical and pathological significance of cord hemangioma remains unclear due to its rarity, and thus an antenatal management regimen remains unestablished. Papadopoulos et al. found 60 % of cord hemangiomas were accompanied by increased maternal serum alpha-fetoprotein (MS-AFP) [
1]. The cause of MS-AFP elevation is not understood, but several authors postulated there is a breakdown of the fetal/amniotic fluid barrier due to cord hemangioma, similar to other conditions with MS-AFP elevation such as neural tube defects, cystic hygromas, and omphaloceles [
1‐
3]. On the other hand, maternal serum human chorionic gonadotropin (MS-hCG) elevates in cases of multiple pregnancy, hydatidiform mole, and trisomy 21, although there has been no report of cord hemangioma with increased MS-hCG. Cord hemangiomas are assumed to increase the risk of perinatal mortality and morbidity [
4‐
8], because they are often associated with intra-uterine fetal death [
2,
5,
6,
9‐
13]. However, some authors have speculated that there is a falsely strong relationship between neonatal morbidity and cord hemangioma because complicated pregnancies tend to be thoroughly examined [
14]. In the latest review by Papadopoulos et al., the authors concluded that intra-uterine fetal deaths caused by cord hemangiomas are rare, and they are more frequently reported when a fetal anomaly co-exists [
1].
We report a case of a prenatally diagnosed giant umbilical cord hemangioma, followed with Doppler studies and associated with elevation of MS-AFP and MS-hCG. The delivery was conducted by Caesarian method at 29 weeks of gestation due to fetal heart failure. This case report focuses on the pathological findings of the cord hemangioma and also contributes for clarifying its clinicopathological significance.
Discussion
In the present case, the mass was located at the umbilical cord 7 mm from its placental insertion. The mass-forming lesions of the umbilical cord include hematoma, thrombosis, varices, aneurysms, and hemangioma. It was relatively easy to diagnose this case as hemangioma pathologically, differentiating the other mass-forming lesions because of the monotonous proliferation of small vessels and the intact-looking original cord vessels seen in this case.
The present case is a giant cord hemangioma which was detected at 24 weeks of gestation and followed for 5 weeks with Doppler studies; the fetus was safely delivered by Caesarean method at the 29th week. A PubMed search of the literature published since 1960 revealed that cord hemangiomas range from 0.2 to 13 cm in diameter, making the present case one of the largest cord hemangiomas ever [
1]. This case is worth reporting because of its unique gestational course with MS-hCG elevation and fetal heart failure associated with cord hemangioma. Pathologically, immunoreactivity for AFP and extramedullary hematopoiesis (EMH) within the tumor vessels are also of value.
MS-AFP elevation has been detected in the majority of reported cord hemangiomas [
1]. Though the exact mechanism of MS-AFP elevation has not yet been identified, several authors speculated it may be due to the breakdown of the fetal/amniotic fluid barrier due to cord hemangioma, since MS-AFP also increases when the fetus has neural tube defects, cystic hygromas and omphaloceles [
1‐
3]. The immunoreactivity of the hemangioma cells for AFP in this case suggested the AFP-producing nature of the umbilical cord hemangioma. AFP is prenatally produced in the yolk sac of the embryo. Some tumors produce AFP, including hepatocellular carcinoma, some germ cell tumors, and hepatoid carcinoma arising from several organs. As for vascular tumors, hepatic hemangioendothelioma has been reported for its association with high serum AFP, though it is controversial if AFP elevation is due to the production by the tumor itself or is a hepatic response to the tumor [
15].
Although an increase in MS-hCG was seen in the present case, hCG producing cells were not detected within the tumor by immunohistochemistry, despite the use of the appropriate positive control. There have been no reports of MS-hCG elevation associated with umbilical cord hemangioma. hCG is mainly produced by syncytiotrophoblasts covering placental villi during pregnancy. MS-hCG elevation sometimes indicates aneuploidy pregnancies, mostly trisomy 21, hence measurement of serum free beta-human chorionic gonadotropin is now utilized in combination with AFP, unconjugated estriol and inhibin alpha to screen for abnormal pregnancy. Since there was no anomaly found in the infant and its placental disc or the mother associated with high MS-hCG concentration, the cord hemangioma might be responsible for MS-hCG elevation in the present case. The instability of fetal and placental circulation caused by the cord hemangioma may influence the hCG release into the maternal blood. It will be clinically important to determine if cord hemangiomas also account for high MS-hCG concentrations.
This is the first report showing EMH in cord hemangioma. There are several reports of EMH in hemangiomas arising from other adult organs, including kidney [
16‐
19], skin [
19‐
21], spleen [
22], small bowel [
23], and adrenal gland [
24]. Some of these reports suggested that hemangioma can potentially generate hematopoietic precursor cells [
20,
21], based on a study showing that the common precursor cell differentiated into both vascular endothelial and hematopoietic cells [
25]. In addition, our precise pathological examination revealed that original umbilical cord vessels and placental capillaries also contained nucleated erythroblasts and myelocytes, suggesting that extramedullary hematopoietic cells entered into the fetal circulation.
Several kinds of vessels have been proposed as candidates for the origin of cord hemangioma, including umbilical artery, umbilical vein, capillaries in Wharton jelly and vitelline capillaries [
1,
12]. The vessels in close proximity to the tumor or encompassed by the tumor have been considered to be the origin of the tumor in previous studies. Since there was no close interaction between tumor vessels and umbilical vessels in the current case, the tumor origin may have been capillaries in the Wharton jelly.
Although several reports have proposed the possibility that cord hemangiomas impair the fetal circulation, the clinical and pathological significance of this rare tumor remains obscure. Our prenatal data showed the size of the tumor and fetal congestive state were well correlated, therefore we postulate that mechanical compression of the umbilical vein by the tumor mass is the most plausible reason for the deterioration of the fetal congestive state. This mechanical compression of the umbilical vessels has been previously proposed as a factor responsible for impaired fetal circulation [
10]. In addition, there are several theories relating to how cord hemangioma affects the fetal circulation, including acting as a shunt and leading to fetal heart failure [
26], and the tumor’s inward growth to the umbilical vessels resulting in stenosis [
6].
Cord hemangiomas result in increased fetal morbidity and mortality, and have been associated with hydramnios, hydrops fetalis, and fetal hemorrhage from a ruptured hemangioma. However, some authors speculate that fetal anomalies co-existing with cord hemangioma may be responsible for fetal morbidity, and cord hemangioma itself is not always lethal to the fetus [
1,
6]. The clinical significance of cord hemangioma remains to be determined. Doppler study is effective for evaluating the fetal congestive state in prenatally diagnosed cord hemangiomas.
Competing interests
The authors declare that they have no competing interests.
Authors’ contribution
KH, YF, TS, AA and TY pathologically diagnosed this case and drafted the manuscript. HO and ST were involved in the delivery and macroscopic analysis of the placenta and umbilical cord. All authors read and approved the final manuscript.