1. Ultrasound Division, ASL Roma B, Rome, Italy;
2. Ultrasound Division, Ceprano Hospital, Ceprano, Italy;
3. Maternal-fetal Department, Niguarda Hospital “ca Granda” Milan, Italy.

Cord cysts

Umbilical cord cyst refers to any cystic lesion associated with the umbilical cord. Cord cysts can be defined as true or false cysts, and may occur in any location along the cord. They are irregular in shape and are located between the cord vessels. Cord cysts are found in 0.4% of pregnancies [1].

True cysts are small remnants of the allantois (allantoid cysts) or the umbilical vesicle. Cysts have epithelial lining of flat or cuboidal uroepithelium and occur at the fetal or placental end of the cord. They can grow up to several centimeters but more often range between 4 and 60 mm in size. True cysts can be associated with hydronephrosis, patent urachus [2], omphalocele [1] and Meckel diverticulum.

False cysts (pseudocysts) are more common. They come from liquefaction of Wharton jelly and may be as large as 6 cm. Compared with the true cysts, the pseudocysts do not have epithelial lining and are most commonly found at the fetal end of the cord. Pseudocysts may be associated with chromosomal anomalies, omphalocele, hemangiomas and patent urachus [3].

Regardless the type of the cord cysts, 20% of them are associated with structural or chromosomal anomalies, especially trisomies 18 and 13.

The cyst may be single (more common) or multiple. While single cysts in the first trimester are associated with favorable pregnancy outcome, the presence of multiple umbilical cord cysts, their persistence in the second and third trimester and their combination with other ultrasonographic abnormalities, is associated with increased risk of miscarriage, aneuploidy or other structural anomalies.

Most probable location of the umbilical cord cysts is near to the cord insertion to the fetal abdominal wall. Prenatal diagnosis of the umbilical cord cysts is possible as early as in the first trimester, from 7th to 13th weeks of gestation. Color Doppler may be helpful in their differentiation from umbilical vessels.

Differential diagnosis includes pseudocysts, omphalo-mesenteric duct cysts, vascular disorders, abdominal wall defects, bladder exstrophy, and urachal anomalies. Prenatal ultrasonographic differentiation between the true cysts and pseudocysts is not possible, but is not so important because both types have been associated with fetal anomalies in some cases.

The cysts tend to resolve by the end of the first trimester. Those that persist beyond 12 weeks and on to the second and third trimester, and the ones that are near the placental or fetal insertion, are more likely associated with chromosomal anomalies [4]. Thus when a cord cyst is encountered, a detailed sonographic survey of the fetus is advisable. Fetal karyotyping is indicated when other anomalies are found or when the cyst persists into the second trimester. If no other anomaly is found, the prognosis is excellent.

Case reports

We report two cases of the cord cysts, the first showing the presence of two cysts early in the first trimester with their subsequent disappearance in the late first trimester and the second one showing an isolated cord cyst in the third trimester.

Case 1

This is the case of a 27-year-old woman (G3P1 - 1 healthy boy and 1 fetal demise at 12 weeks) with non-contributive personal and family history.

Her first ultrasonographic examination was performed at 8 weeks + 4 days. Fetal biometry was consistent with dates. Two anechoic structures of 4 and 8 millimeters in diameter were observed adjacent to the cord. No color flow within the structures was present. The cysts were near the fetal side of the umbilical cord.

The patient had declined dual biochemical test. Her following examination was done at 13 weeks. Nuchal translucency was 1.3 mm for a crown rump length of 68 mm, nasal bone was present, ductus venous “a” wave was antegrade, there was no tricuspid regurgitation, heart examination seemed to be normal and there were no detectable fetal anomalies present. Umbilical cord had 3 vessels and the cord cysts weren’t visible anymore. Furthermore, no fetal anomalies were detected at anomaly scan performed at 21 weeks.

Pregnancy evolved uneventfully until term and a healthy boy of 3150 grams and Apgar score 9/10 at 1/5 min respectively was born spontaneously at 39 weeks. Karyotype was normal 46, XY.

This case confirms that most cord cysts disappear by the end of the first trimester and these ones are usually not associated with fetal or karyotype anomalies.

Here are some images and videos showing both cysts at 8 weeks and normal finding at 13 weeks of pregnancy.

Images 1-7 and videos 1, 2: 8 weeks of gestation - umbilical cord with two cysts.

 

Images 8-10 and video 3: 13 weeks - normal umbilical cord without cysts

Case 2

This was a 34-year-old woman (G1P0) with non-contributive history that was scanned at 32 weeks. A cord cyst of 36x20 mm was found close to the placental cord insertion. Fetal growth was restricted (around 25th percentile). Fetal and placental Doppler were normal and there were no fetal anomalies or aneuploidy markers present. Polyhydramnios (AFI 28 cm, deepest vertical pocket 9 cm) was also noticed.

The patient neither did undergo amniocentesis nor biochemical test. Previous ultrasonographic examinations performed elsewhere did not report presence of the cord cyst. Spontaneous delivery occurred at 39 weeks and a male newborn of 2750 g and Apgar score 9/9 at 1/5 min respectively was born. The finding of the cyst at the placental end of the cord was confirmed.

The only concomitant findings were a small for gestational age fetus and polyhydramnios. No congenital anomalies were found and following karyotyping has turned out to be normal. The case confirms that if no other fetal anomalies are present, the prognosis of the isolated umbilical cord cyst is usually excellent.

Images 11-18: 32 weeks - the images show umbilical cord cyst adjacent to the placental end of the cord. The cyst is avascular and surrounded by the vessels of the cord.

Image 199: 32 weeks - polyhydramnios.

 

References

1.Ratan SK, Rattan KN, Kalra R, Maheshwari J, Parihar D, Ratan J. Omphalomesenteric duct cyst as a content of omphalocele. Indian J Pediatr 2007;74:500-2.
2.Bunch PT, Kline-Fath BM, Imhoff SC, Calvo-Garcia MA, Crombleholme TM, Donnelly LF. Allantoic cyst: a prenatal clue to patent urachus. Pediatr Radiol 2006;36:1090-5.
3.Kilicdag EB, Kilicdag H, Bagis T, Tarim E, Yanik F. Large pseudocyst of the umbilical cord associated with patent urachus. J Obstet Gynaecol Res 2004;30:444-7.
4.Sepulveda W, Gutierrez J, Sanchez J, Be C, Schnapp C. Pseudocyst of the umbilical cord: prenatal sonographic appearance and clinical significance. Obstet Gynecol 1999;93:377-81.
5.Chen CP, Jan SW, Liu FF, Chiang S, Huang SH, Sheu JC, et al. Prenatal diagnosis of omphalocele associated with umbilical cord cyst. Acta Obstet Gynecol Scand 1995;74:832-5.