OMPHALOMESENTERIC DUCT CYSTS

VITTELINE DUCT CYSTS

VESICOALLANTOIC CYST

OMPHALOMESENTERIC DUCT CYSTS

In early embryonic life the omphalomesenteric duct serves as a communication between the midgut and yolk sac. The duct usually obliterates between the 9th and 18th menstrual weeks (1).

The omphalomesenteric duct cyst is an embryologic remnant of the yolk stalk. If the yolk stalk does not obliterate completely, various portions may persist giving rise to Meckel's diverticulum, intraabdominal cyst, enteric fistula to the umbilicus, or a cystic or polypoid umbilical cord mass may be observed (2).

The cysts are lined by a columnar mucin-secreting epithelium. Eventually these cysts may contain gastric, colonic, pancreatic and / or small intestine epithelium(3,4).

ULTRASOUND

• Cystic mass near the fetal end of the umbilical cord.
• Located close to the periphery of the cord (allantoic cysts are central).
• May reach sizes of up to 6 cm.
• Avascular on color doppler.
• More common in male fetuses (4:1 ratio) (3).
• Usually of no consequence to the fetus. One case of fetal hemorrhage (4) (from the umbilical vein) and exanguation from gastric mucosa in the cyst that eroded the umbilical vessels.
• Half as common as allantoic cysts.

PROGNOSIS

• Rosenberg (5) - uneventful course in one fetus.
• Skibo and co-workers (6) - report on eight cases of cystic masses of the umbilical cord detected endovaginally at 8-9 weeks gestation. Seven resolved spontaneously by 12 weeks gestation age.
• Zimmer and Bronshtein (7) reported on four cases of intra-abdominal cysts detected endovaginally. Two resolved spontaneously, one was terminated because of other associated anomalies and one died in utero.
• McCalla and co-workers (8) present a case of an intra-abdominal cyst that migrated to for an umbilical cord cyst leading to fetal death.

VESICOALLANTOIC CYST

A vesicoallantoic cyst is a single communication cavity between a cyst in the umbilical cord and the fetal urinary bladder (9-11).

• The communication between the allantois and the urachus usually closes during the early stages of gestation.
• If this communication fails to disappears, the fetal urinary bladder, urachus and allantois for a single communicating cavity that is filled with fetal urine.
• Ultrasound demonstrates a dumbbell cystic mass at the base of the cord that communicates with the fetal urinary bladder, and empties and fills with fetal urination (9). The umbilical vessels are normal.
• Numerous antenatal cases have been described. The cord cyst generally regresses prior to birth but may persist postnatally.

24 weeks of gestation
	Vesico-allantoic cyst (**) in the base of the umbilical cord communicating with the fetal bladder
	Another example at 29 wks of gestation

REFERENCES

1. Moore KL. The developing human. Second edition. Philadelphia: WB Saunders 1977.
2. Romero R, Pilu G, Jeanty P et.al. Prenatal diagnosis of congenital anomalies. Norwalk: Appleton and Lange 1988;391-397.
3. Heifetz SA, Rueda-Padraza ME. Omphalomesenteric duct cysts of the umbilical cord. Pediatr Pathol 1983;1:325-335.
4. Blanc WA, Allen GW. Intrafunicular ulceration of persistent omphalomesenteric dust with intraamniotic hemorrhage and fetal death. Am J Obstet Gynecol 1961;82:1392-1396.
5. Rosenberg J, Chervenak F, Walker B et.al. Antenatal sonographic appearance of omphalomesenteric duct cyst. J Ultrasound Med 1986;5:719.
6. Skibo LK, Lyons EA, Levi CS. First trimester umbilical cord cyst. Radiology 1992;182:719.
7. Zimmer E, Bronshtein M. Fetal intra-abdominal cysts detected in the first and early second trimester by transvaginal sonography. J Clin Ultrasound 1991;19:564.
8. McCalla CO, Lajinian S, DeSouza D, Rottem S. Natural history of antenatal omphalomesenteric duct cyst. J Ultrasound Med 1995;14:639-640.
9. Shakunami K, Tsuji T, Kotsuji F. Prenatal sonographic features of vesicoallantoic cyst. Ultrasound Obstet Gynecol 2000;15:545-546.
10. Yoo SJ, Lee YH, Ryu HM et.al. Unusual fate of vesicoallantoic cyst with non-visulaization of the fetal bladder in a case of patent urachus. Ultrasound Obstet Gyencol 1997;9:422-424.
11. Tolaymat LL, Maber JE, Kleinman GE et.al. Persistent patent urachus with allantoic cyst: a case report. Ultrasound Obstet Gynecol 1997;10:366-368.