ANATOMIC PATHOLOGY
Single Case Reports
An Unusual Venous Anomaly
of the Placenta
GEON KOOK LEE, M.D., JE G. CHI, M.D., AND KYUNG SUP CHA, M.D.
The authors present an unusual vascular anomaly of the placenta.
The placenta was very large, weighing 1,490 g. On the fetal
surface, numerous dilated and tortuous vessels were observed on
and under the chorionic membrane, of which three branches arose
from a vein that was connected to the umbilical vein. One of
them had a 5 X 2.5 cm aneurysmal dilatation, where three secondary branches arose. These venous channels were dilated and
tortuous. The longest secondary branch was 133 cm in length
and 1.2 cm in mean diameter and led into the placenta. Multiple,
severely coiled or straight small branches arising from these
vessels were also observed as vascular tangles. Some of these
smaller vessels also led into the placenta. All abnormal vessels
were veins. The umbilical cord was also normal except for a
membranous insertion, and the placenta was unremarkable except for its large size. (Key words: Placenta; Venous malformation; Fetus) Am J Clin Pathol 1991;95:48-51
Various anomalies of the placenta and umbilical cord have
been described, but the previous discussions concerning
them have focused mainly on the site of placentation or
on the shape or mode of insertion of the umbilical cord.1
There have been no referable reports describing anomalies
of the chorionic vessels.1,2 However, venous malformation
of the chorionic vessels of the placenta is an important
lesion because it can potentially endanger the fetus's life.
We present a very unusual case of a venous anomaly
of the chorionic vessel. Tangles of anomalous vessels resembling crowded intestinal loops were found with a large
placenta. The rarity of this condition and interest in its
possible pathogenesis prompted this report.
After delivery of the baby, the obstetrician found intestine-like structures in the uterine cavity. He suspected that they could be the intestinal
loops that belonged to a regressed twin. A possibility of vascular anomaly
was also suspected.
The neonate was 2.01 kg in birth weight and showed signs of respiratory
distress soon after birth. She underwent perinatal care with incubator
and oxygen supply. She showed anemia, with a hemoglobin level of 3.5
mmol/L (5.6 g/dL). After a transfusion and other conservative measures,
she recovered and did well. The mother showed no signs of illness related
to the delivery.
PATHOLOGIC EXAMINATION
The placenta was very large and fragmented irregularly
into
three pieces. These measured 25 X 12 X 6.5 cm, 11
REPORT OF A CASE
X
9
X
4 cm, and 7 X 6 X 3.5 cm, respectively. The total
A 30-year-old woman delivered a female baby at 36 weeks gestation.
weight,
including the umbilical cord and abnormal vessels,
The pregnancy was uneventful until the 35th week, when ultrasonographic examination showed partial placenta previa and intrauterine
was 1490 g. The estimated volume of the fragments was
growth retardation. The biparietal diameter was 7.6 cm and the foot
2493 mL. The reconstructed placenta was bean shaped,
length was 5.6 cm. Soon after, labor pain developed and the membranes
and the concave defect had probably been filled with the
ruptured. The baby was delivered by emergency cesarean section.
tangled mass of the abnormal vessels. The fetal surface
showed numerous dilated and tortuous vessels on and
From the Department of Pathology, Seoul National University Chil- under the chorionic membrane (Fig. 1). Division of the
dren 's Hospital, and Department of Obstetrics and Gynecology, CHAcotyledons was exaggerated. There were several scattered
Hospital, Seoul, Korea.
small fibrin deposits. Microscopic examination showed
that
the villi were normally formed. The vessels were patReceived January 30,1990; received revised manuscript and accepted
for publication May 21, 1990.
ent, without obliteration or thickening. The stroma was
Address reprint requests to Dr. Chi: Department of Pathology, Seoul
not edematous. The trophoblasts were unremarkable. InNational University Children's Hospital, 28 Yunkun-Dong, Chong-no
tervillous
fibrin deposits were seen in small areas.
Ku, Seoul 110-744, Korea.
48
LEE, CHI, AND CHA
49
Venous Anomaly of the Placenta
tiary branch of another were traced to the point of insertion into the placenta. The tertiary branch with the inserted end measured 20 cm in length and 1 cm in diameter. The others had free ends. The vessels were
tortuous and had multiple alternating dilations and narrowings. They had multiple, severely coiled or straight
small branches, some of which also had connections to
the placenta. All the vessels were covered by a loose, glistening, and myxoid membrane (Fig. 1). Histologically,
the vessels had muscular layers of varying thickness and
were covered by myxoid stroma (Fig. 3). The myxoid
stroma was very similar to Wharton's jelly. There were
focal inflammatory cell infiltrations in some portions of
the chorionic and amniotic membranes.
DISCUSSION
FlG. 1. Overall feature of the placenta after reconstruction of fragmentary specimens. Intricately tortuous, diffusely and segmentally dilated
vascular channels are seen free or inside the fetal membrane (left corner).
The normal umbilical cord (arrow) is inserted in a velamentous fashion,
and the umbilical vessel is continuous to the abnormal vessels. The abnormal vessels are partly or totally covered by a thin glistening membrane.
The umbilical cord was 22.5 cm in length and 0.7 cm
in diameter and had two arteries and one vein. It was
inserted in a velamentous fashion (Fig. 1). The umbilical
vessels were connected to three vessels: two arteries and
one vein. The arteries were 3.5 cm in length and 0.2 cm
in diameter. The arteries were torn during manipulation,
and their distal portions could not be traced. The vein
was connected to three branches at 3 cm distal portion.
Two branches were 11 cm and 8 cm in length and 0.6
cm and 0.5 cm in diameter, respectively. Their distal portions were also torn. The third branch was 0.6 cm in diameter and had a 5 X 2.5 X 2.5 cm aneurysmal dilatation
at the point of 21 cm distal to the branching site. From
this aneurysmal dilatation, three new secondary branches
arose (Fig. 2). The longest secondary branch measured
133 cm in length and 1.3 cm in mean diameter, and the
others were 24 cm and 21 cm in length and 0.6 cm in
diameter, respectively. One secondary branch and a ter-
Various anomalous conditions associated with the placenta and umbilical cord are reported, of which many are
associated with fetal anomalies. Although many vascular
anomalies have been seen on the surface of the placenta,
the type of malformation seen in this case has been unreported heretofore.
This case represents an anomaly of the chorionic vessels, accompanied by an unusual shape and striking overweight of the placenta. The anomaly was characterized
by the arborizing and anastomosing vascular channels that
were obviously of venous origin grossly and histologically.
The chorionic vessels are of fetal origin; therefore, this
vascular anomaly should be classified as a fetal vascular
malformation. Because there is a possibility of communication between umbilical vein and these anomalous
vessels in the chorion, one could also refer to this lesion
as a variant of placental arteriovenous malformation.
However, no direct arteriovenous communication was
demonstrated during dissection. In addition, microscopic
examination of the villi did not show any evidence of
increased pressure at the level of villous capillaries. Accordingly, this anomaly may best represent an unusual
venous malformation of chorionic vessels.
The fact that the fetus survived without any significant
problem indicates that the carbon dioxide content was
not increased significantly in the blood circulating through
these anomalous venous channels. However, the placenta
was certainly abnormal in weight and size. At 36 weeks'
gestation, the average weight of the placenta among Koreans is 467 g and the volume is 573 mL. 3 They were
1490 g and 2493 mL, respectively, in this case. The placental disk showed an increased thickness, measuring
3.5-4 cm, as compared with 1.5 cm in the usual placenta.
Therefore, although the vascular mass is reduced, the actual placental mass is still much larger than the average.
Vol. 95 • No. I
ANATOMIC PATHOLOGY
50
Single Case Reports
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FIG. 2 (upper). The abnormal vessels show aneurysmal dilatations and secondary branches. Three branches derive from a dilated segment.
FIG. 3 (lower). Photomicrograph of a dilated vessel. It is composed of thin intima, media with a moderate amount of smooth muscle, and myxoid
adventitia. The constituents of the outer myxoid layer are reminiscent of Wharton's jelly. Hematoxylin and eosin (X400).
51
LEE, CHI, AND CHA
Venous Anomaly of the Placenta
This placental vascular aberration appears to be a very
early anomaly in embryonic life. The chorionic vessels
are supposedly formed by the branching of the umbilical
vessels. As the direction of flow from the fetus is established, a minimum number of necessary vessels remain,
and the balance of the vascular plexus disappears.1,2 This
regressive process might have been halted or interrupted
in this case by indefinite intrauterine factors.
The fact that this sort of anomaly has not been reported
previously indicates its very low incidence. However, obstetricians and pathologists should be aware of the exis-
tence of this abnormality because it could potentially be
confused with bowel loops, as occurred in this case.
REFERENCES
Benirschke K, Driscoll SG. The pathology of the human placenta.
New York: Springer-Verlag, 1974:1-72.
Bennington JL. Pathology of the placenta, vol 8. Major problems
in pathology. London: WB Saunders, 1978:106-134.
Park TD, Chi JG, Lee SK, Kim SW. Studies on placentas among
Koreans—gross and microscopic examination of 4,000 consecutive placentas. Korean Journal of Pathology 1986;20:12-25.
Neuroendocrine Carcinoma of the
Ampulla of Vater
A Case of Absence of Somatostatin in a Vasoactive
Intestinal Polypeptide-, Bombesin-, and
Cholecystokinin-Producing Tumor
SERGIO SANCHEZ-SOSA, M.D., ARTURO ANGELES ANGELES, M.D.,
HECTOR OROZCO, M.D., AND JORGE LARRIVA-SAHD, M.D., Ph.D.
A 31-year-old patient with a clinical picture of obstructive jaundice had surgical treatment, and a primary carcinoid of the ampulla of Vater (VA) was found. The tumor was studied with light
microscopy, immunohistochemistry, and electron microscopy.
The neoplasm had histopathologic and cytopathologic features
similar to those encountered in typical neuroendocrine neoplasms.
It is interesting that immunohistochemical techniques disclosed
the presence of vasointestinal polypeptide, cholecystokinin, and
bombesin; however, unlike most neuroendocrine neoplasms arising in VA, no somatostatin-immunoreactive cells were found.
(Key words: Neuroendocrine carcinoma; Carcinoid; Ampulla of
Vater, Immunohistochemistry, Ultrastructure) Am J Clin Pathol
1991;95:51-54
Moreaux and colleagues4 reviewed the largest series of
carcinoids of the VA in which 19 cases were reported.
From all cases diagnosed as carcinoids of the VA, only
nine have been documented by immunohistochemical
techniques, and one of those nine cases had neither somatostatin-immunoreactive (S-I) cells nor other peptides.15-8
From the Departamento de Patologia, Institute Nacional de la NutriIn the current report we describe the second case of a
tion, Salvador Zubiran, Tlalpan, Mexico.
VA neuroendocrine carcinoma in which no S-I cells were
identified. However, unlike the previous case, a coexisReceived January 8, 1990; received revised manuscript and accepted
for publication April 24, 1990.
tence of vasoactive intestinal polypeptide (VIP), bombesin
Address reprint requests to Dr. Larriva-Sahd: Department of Pathology,
Instituto Nacional de la Nutricion, S.Z., Calle Vasco de Quiroga No. 15, (BB), and cholecystokinin-immunoreactive- (CCK) producing cells was documented.
Mexico 14000, D.F., Mexico.
Neuroendocrine neoplasms of the duodenum constitute
5% of all gastrointestinal (GI) carcinoids.1 Among these,
primary involvement of the ampulla of Vater (VA) is rare.2
Thus, Sanders and Axtell,3 in a review of 2,502 cases of
GI carcinoids, found only 5 within the VA. More recently,
Vol. 95 • No. I