Lorraine

K. Skibo,

MD

Edward

#{149}

First-Trimester Cystic

masses

have

been

3rd

trimesters

ation fects

of the

MD

Clifford

S. Levi,

#{149}

Umbilical

umbilical

detected

A. Lyons,

Cord

Cysts’

cord

in the 2nd

of pregnancy

MD

and

in associ-

with fetal abdominal wall deand chromosomal anomalies.

With high-resolution ultrasound (US), can be visualized

mester.

Their

endovaginal umbilical cord cysts during the 1st tn-

origin

and

significance

must be considered for proper obstetnc management. The authors report eight cases in which cystic masses of

the umbilical

cord

were

detected

dun-

ing

US examinations performed at 8-9 weeks menstrual age. In the five cases followed to term, both the in-

fant and the umbilical cord were found to be normal at physical examination. Sonographically, all cysts appeared to be eccentric in relation the umbilical cord, and, although

to all

were closer to the fetus, the cysts were clearly extraembryonic. Cyst size was 2.0-7.5 mm (mean, 5.2 mm). Seven cysts resolved by 12 weeks menstrual age. The incidence of cysts in patients who underwent US at the authors’ institution between 8 and 12 weeks menstrual age was 0.4%; the true frequency is unknown without

routine patients.

1st-trimester

Index terms: Fetus, Fetus, US, 856.12984 856.12984 #{149} Umbilical Radiology

1992;

scanning

of all

abnormalities, 856.879 #{149} Pregnancy, US, cord, 856.879

182:719-722

b.

a. Figure strual

1. age.

T

(a) Endovaginal (b) Endovaginal

HE detection

cysts

US scan US scan

of umbilical ultrasound

with

demonstrates of same patient

cord (US) has

location,

have

described

allantoic

can and during

should be readily the 1st trimester.

for dating tion, and

umbilical findings in which

Once

were

de-

before therapeutic abonthe differential diagnosis

I From the Section of Diagnostic Ultrasound, Department of Radiology, Health Sciences Centne, 820 Sherbrook St. Winnipeg, Man, Canada R3A 1R9. Received June 21, 1991; revision requested July 23; revision received September 6; accepted October 2. Address reprint requests to E.A.L. ‘

RSNA,

1992

the

patient

2nd-

and

cyst

should

affect

and

the

fetus?

3rd-trimester

is

an umbili-

management

of

The

of

cysts

temporal

aid in clinical

behavior,

may

decision

outcome

AND

METHODS

All cases in which 1st-trimester cystic masses of the umbilical cord were detected sonographically from September 1989 to March 1991 were reviewed. All sonograms

cord cysts. The are described in US was performed

discovered,

and

MATERIALS

discussed. cal cord

mass at 9 weeks menresolution of the cyst.

cysts

Herein, we report the findings and fetal outcome in eight cases of 1sttrimester histologic one case

cystic shows

making.

and pseudocysts to be associated with fetal abdominal wall defects and chromosomal abnormalities. Two cases of 1st-trimester umbilical cord cysts detected with transabdominal US have been reported (4). With high-resolution endovaginal US, umbilical cord cysts tected

cord later

eventually

been reported in the 2nd and 3rd tnmestens of pregnancy (1-3). Published reports

umbilical 2 weeks

docu-

mented in the literature indicates the need for careful evaluation of any fetus in whom an umbilical cord cyst is found. Exploration of the physical characteristics of the cyst, such as size,

obtained

with

an endovaginab

ap-

proach. Eight cases of cystic masses of the umbilical cord were discovered in a total of approximately 2,070 patients examined at 8-12 weeks menstrual age. Examinations were performed for unsure dates (n = 4), vaginal bleeding (n = 2), possible ectopic pregnancy (ii = 1), or amenorrhea (n = 1). Follow-up examinations were performed until cyst resolution and during the 2nd trimester to exclude sonographically detectable fetal anomalies. Five patients were followed up to term, one was lost to follow-up, one terminated the pregnancy with a previously arranged therapeutic abortion, and one had not

been

delivered

of the baby

at the time this

article was written. In the five cases followed to term, the newborn, umbilical cord, and placenta were physically exammed to identify any abnormalities. One umbilical cord cyst was discovered sonographically in the 1st trimester in January 719

Patient

Parameters Detected

Patient I 2 3 4

Indication

Resolved Menstrual

Menstrual Aget

for Scan 9 8 8 8

5 6

Dates Bleeding Bleeding Exclude ectopic pregnancy Dates Dates

wk wk wk wk

(23.3) (19.7) (21.0) 5 d (20)

7

Dates

8 wk (16)

8

Dates

8 wk 6 d (18)

8 wk (17.1) 8 wk 6 d (21.4)

Cyst Size

Cord Size

Age

(mm)

(mm)

Ratio

11 wk 10 wk 2 d 9 wk 5 d 11 wk

7.5 6.0 5.0 6.0

2.0 3.0 3.5 3.0

3.8 2.0 1.4 2.0

Eccentric; Eccentric; Eccentric; Eccentric;

middle of cord middle of cord near fetus near fetus

Normal newborn Normal newborn Lost to follow-up Normal newborn

12 wk 10 wk 4 d

6.8 6.0

4.0 2.0

1.7 3.0

Eccentric; Eccentric;

near near

Normal Normal

2.0

2.0

1.0

Eccentric;

near fetus

Therapeutic

2.2

2.0

1.1

Eccentric;

middle

Estimated

. . .

16 wk

Cyst/Cord

Position

and

Location

of Cyst

Outcome

fetus fetus of cord

newborn newborn

abortion date

of concep-

tion 11/91 Numbers

*

in parentheses

are crown-rump

length

(mm).

-= .‘

.

.,fr#{149}

1:#{149}#{149}#{149}.. *:)i’:’ ,/i.:

;_--:.

#{149}.t---T Figure

2. Color Doppler endovaginal image of embryo at 8 weeks menstrual demonstrates umbilical cord vessels around cystic mass.

(‘/

US age coursing

.

-. a. Figure

1991 during preoperative assessment before a therapeutic abortion. The products of conception were obtained after the abortion for pathologic examination.

,.

:,;::1_d4:1

....

...

#{149}

.

S

..

b. 3.

(a) Low-power

photomicrograph

of umbilical

cord

g.d*p#{149}

in semilongitudinal

section

shows amniotic inclusion cyst (arrowhead) and, lateral to that, area of mucoid degeneration in Wharton jelly (hematoxylin-eosin stain; original magnification, x25). (b) Close-up view of amniotic epithelial inclusion cyst with flattened cuboidal cell lining on delicate basement membnane (hematoxylin-eosin stain; original magnification, x250).

RESULTS Menstrual age of the embryo at the time of discovery of the cystic mass was 8-9 weeks. All cystic masses were smooth in contour and round to oval in shape, with normal wall thickness and anechoic contents (Fig 1). All cysts appeared to be eccentric with respect to the central axis of the cord and clearly extnaembryonic; most were located closer to the embryo than to the placental insertion. The

cord

that

intervened

between

the cyst

and the embryo was normal. Color Doppler US demonstrated the cord vessels coursing around the cyst (Fig 2). Mean cyst size was 5.2 mm (range, 2.0-7.5 mm). Cord width at the time of discovery was 2.0-4.0 mm (mean, 2.4 mm). The ratio of cyst size to adjacent cord width was 1.0-3.8 (mean, 2.0) (Table). The frequency of cystic masses in the umbilical cord was 0.4% in patients with live intrauterine gestations who were examined between 8 and 720

#{149} Radiology

12 weeks menstrual age. In all patients, the cysts disappeared by 12 weeks menstrual age (range, 9 weeks 5 days to 12 weeks). In five cases, the cyst was gone within 2 weeks of the initial US examination. At the time of delivery, physical

examination of five infants normal findings, and visual tion and physical umbilical cords ities. One patient

low-up

before

yielded inspec-

examination of the revealed no abnormalwas lost to fob-

delivery.

In the one case for which pathologic data were available, histologic examination of the cystic mass in the umbilical cord revealed a cystic space lined with amniotic-type epithelium, compatible with an amniotic inclusion cyst (Fig 3). Adjacent to the cyst, areas of mucoid degeneration of the umbilical cord were seen. A similar finding of mucoid degeneration adjacent to an albantoic cyst was reported by Sachs

et ab (1).

DISCUSSION When the the umbilical longitudinal

embryo is 35 mm long, cord is created when and transverse fobdings

of the tnibaminar poses

the

embryonic

body

stalk

and

disk the

stalk (5,6). The body stalk the embryo to the placenta tains the umbilical arteries,

ical vein, tois

and

the

develops

urogenital chus

though

sinus, the

allan-

of the body with

becoming

as its cavity

hindgut

The

a recess

sac that projects into the and remains in continuity

ap-

yolk

connects and conthe umbib-

ablantois.

from

allantoic

the

uraAl-

connection when

yolk

stalk the

is obliterated.

is removed

the

the

to the cboaca

divides, dilatation of allantoic remnants has been found in the umbilical cord in fetuses up to 14 weeks menstrual The

duct stnicted

age. omphabomesentenic

forms by

as the the

yolk

folding

or vitelbine

sac is conembryo;

it

March

1992

masses our

of the

umbilical

knowledge,

previously. Cystic

masses

include

cord

not

been

of the

those

has,

to

reported

umbilical

derived

from

cord

the

omphalomesenteric and the allantois. tion reveals that

or vitelline duct Pathologic examinathese masses charac-

tenisticalby

near

the

occur

umbilical

enteric

cord

duct

the

fetal

end

of

(8). Omphalomes-

cysts

are

lined

with

co-

bumnar mucin-secreting cells, and allantoic cysts are lined by a single layer of flattened epithebium. Although pathologic distinction among amniotic inclusion cysts, omphalomesenteric duct cysts, and allantoic cysts is possible,

sonographic

is not. Focal cord

differentiation

enlargements

may

occur

of the with

umbilical

accumulation

of

Wharton jelly or edema fluid (3); neithen process should possess the charFigure

4.

of embryo inclusion hemangioma

OMC

=

umbilical

Diagram of and fetus at cyst, BOWEL or other omphalomesenteric vein, UVV =

umbilical cord displays normal constituents and possible cystic masses less than 12 weeks menstrual age. AC = allantoic cyst, AIC = amniotic = intestinal tract temporarily herniated into proximal cord, HEM = neoplasm, MUC = mucoid degeneration or edema of Wharton jelly, duct cyst, UA = umbilical artery, UB = urinary bladder, UV = umbilical vein vanix.

acteristics

of a true

cyst,

Anomalies

rebated

tures of the umbilical umbilical vein varix may

appear

cystic

masses

tunes

of the

(b)

Color

US image of region

of embryo shows flow,

reveals possible excluding true

cystic cystic

mass mass.

of umbilical

cord.

with

flow

5). Umbilical

rare,

and

most

mas.

Sonographic

cysts

masses

to the cord, narrow

Volume

outer

surface

which becomes origin at the

182

#{149} Number

of the

umbilical

constricted umbilicus 3

to a (5,6).

The

embryologic

contents for

features

of the

and

umbilical

cord

allow

cystic

masses

to

six potentially

occur: (a) amniotic (b) omphabomesentenc (c) allantoic cysts,

inclusion duct (d) vascular

lies, jelly

and (Fig 4).

Amniotic entrapped during

a narrow

inclusion within

its formation

may

cyst to the amniotic bilical cord. These

amorphous stration

amniotic

cysts

epithelium

tract

cysts, cysts, anomaWharton

(f)

(e) neoplasms, disturbances

amniotic

debris. or clinical

inclusion

ing

that

the

represent has

they

cord

(7).

Occasionally,

extend

from

the

surface of the umcysts may contain

Ultrasonic

demon-

consideration

cysts

as cystic

of

3rd

struc-

septations are

rarely

umbilical

and

reported

have

cord

seen, could

detected

dun-

trimesters

have

to be associated

with

fetal abnormalities. Jauniaux et al (3) reported two cases of trisomy 18 in which large pseudocysts of the umbilical cord were found at 26 and 32 weeks menstrual was also detected series

been

umbilical

been

2nd

are

as

or as cystic

Although

the

tumors

hemangio-

tumors

appear to be cystic. Umbilical cord cysts joins the primitive midgut to the cxtraembnyonic yolk sac. The omphabomesentenic duct and its accompanying vessels form the yolk stalk. The connection of the omphabomesenteric duct to the yolk stalk is also obliterated by 8 weeks menstrual age, abthough traces of the duct within the umbilical cord have been described. The umbilical cord contents are surrounded by Wharton jelly, a mesenchymal tissue rich in mucopolysacchanides. The amniotic cavity eventually envelops the entire embryo. Amniotic epithelium is applied

without

multiple

of the

US of

examinations

these

teratomas

the

cord

cord

represent

containing

(12,13).

during

umbilical

and

(Fig

tunes

as an

US can enable difvascular struc-

flow

echogenic

b. (a) Endovaginal Doppler US scan

struc-

Examination

Doppler between

demonstrated 5.

small

cord, such or hematoma,

(10,11).

with color ferentiation

Figure

the

to vascular

to be cystic

examination

a.

but

size and surrounding amniotic fluid limit application of cyst criteria. With mucoid degeneration of the umbilical cord, a cystic appearance has been reported at US (9).

of nine

age; an omphalocele in one fetus. In the omphalocebes

nosed with US in utero Fink and Filly (2), three

had toic

sonographically cysts. One case

onstrated allantoic omphabocele

the

(Fig

by also

detectable in our series

reported

umbilical

diagreported fetuses

cord 6) and

allandem-

association cysts

of

with

ended

an

in

stillbirth. Radiology

#{149} 721

Although histologic evidence in one 1st-trimester umbilical cord cyst demonstrated an amniotic inclusion cyst, we can only speculate as to the origin of the remaining cord cysts in our series. Regardless of the origin, two clinical outcomes of umbilical cord cysts become distinct. Secondand 3rd-trimester umbilical cord cysts that persist are frequently accompanied by fetal anomalies. Finst-tnimesten umbilical cord cysts that resolved in our small series were associated with a normal outcome. The discovery of umbilical cord cysts in 0.4% of patients examined at 8-12 weeks menstrual age is remarkable and is in part accounted for by the performance of high-resolution endovaginab US scanning. Although

increasing

resolution

tion and umbilical

facilitates

#{149} Radiology

1.

2.

Sachs L, FourcroyJL, Wenzel DJ, Austin M, Nash JD. Prenatal detection of umbilical cord allantoic cyst. Radiology 1982; 145: 445-446. Fink IJ, Filly RA. Omphalocoele associated with umbilical cord allantoic cyst: sonographic evaluation in utero. Radiology 1983; 149:473-476.

3.

4.

5.

6.

7.

detec-

physical characterization of cord cysts, pathologic differentiation is currently impossible. We have documented a new 1sttrimester sonographic finding. Small 1st-trimester umbilical cord cysts that resolve and are not associated with fetal anomalies may not be clinically significant. U

722

References

8.

9.

10.

11.

Jauniaux E, Donner C, Thomas C, Francotte J, Rodesch F, Avni FE. Umbilical cord pseudocyst in trisomy 18. Prenat Diagn 1988; 8:557-563. Rempen A. Sonographic first trimester diagnosis of umbilical cord cyst. JCU 1989; 17:53-55. Moore KL. The developing human: clinically oriented embryology. 4th ed. Philadelphia: Saunders, 1988; 65-68. Cullen TS. Embryology, anatomy and diseases of the umbilicus. Philadelphia: Saunders, 1916; 1-33. deSa DJ. Diseases of the umbilical cord. In: Pernin EV, ed. Pathology of the placenta. New York: Churchill Livingstone, 1984; 134-136. Hill LM, Kislak S. Runco C. An ultrasonic view of the umbilical cord. Obstet Gynecol Surv 1987; 42:82-88. laccarino M, Baldi F, Persico 0, Palagiano A. Ultrasonographic and pathologic study of mucoid degeneration of umbilical cord. JCU 1986; 14:127-129. Jeanty P. Fetal and funicular vascular anomalies: identification with prenatal US. Radiology 1989; 173:367-370. Vesce F, Guerrini P, Perri C, Carazzini L, Simonetti V. Ultrasonographic diagnosis of ectasia of the umbilical vein. JCU 1987; 15:346-349.

Figure

6.

Endovaginal

US image

of fetus

in

2nd trimester demonstrates large abbantoic cyst (arrowheads) and omphalocele (arrows). Spontaneous abortion occurred shortly after scan was obtained, and chnomosomal analysis revealed trisomy 18.

12.

13.

Ghidini A, Romero R, Eisen R, Smith W, Hobbins JC. Umbilical cord hemangioma: prenatal identification and review of the literature. J Ultrasound Med 1990; 9:297300. Jauniaux E, Campbell S, Vyas S. The use of color Doppler imaging for prenatal diagnosis of umbilical cord anomalies: report of three cases. Am J Obstet Gynecol 1989; 161: 1195-1

197.

March

1992