Sonographic Spectrum of Hemorrhagic Ovarian Cysts Image Presentation Kiran A. Jain, MD

Transcription

Sonographic Spectrum of Hemorrhagic Ovarian Cysts Image Presentation Kiran A. Jain, MD
Image Presentation
Sonographic Spectrum of
Hemorrhagic Ovarian Cysts
Kiran A. Jain, MD
Objective. To present the spectrum of sonographic findings associated with hemorrhagic ovarian
cysts. Methods. Experience with making specific and correct diagnosis of hemorrhagic cysts with the
use of sonography was reviewed, and the spectrum of sonographic findings was identified. Results.
Endovaginal sonography facilitated excellent visualization of internal architectural details of an adnexal mass, which enabled specific diagnosis of hemorrhagic cysts instead of other adnexal masses.
Conclusions. A hemorrhagic cyst is a common and important entity to recognize and diagnose correctly, and because it can be confused with more ominous conditions, it is important to recognize its
specific diagnostic patterns. Key words: cystic mass; hemorrhagic cysts; reticular pattern; sonogram.
Abbreviations
hCG, human chorionic gonadotropin; HOC, hemorrhagic ovarian cyst
Received March 1, 2002, from the Department of
Radiology, University of California Davis Medical
Center, Sacramento, California. Revision requested
March 28, 2002. Revised manuscript accepted for
publication April 10, 2002.
Address correspondence and reprint requests to
Kiran A. Jain, MD, Department of Radiology,
University of California Davis Medical Center, 4860
Y St, Suite 3100, Sacramento, CA 95817.
A
hemorrhagic ovarian cyst (HOC), although
frequently encountered during routine pelvic
sonography, is a great imitator.1 Hemorrhagic
cysts have a variety of imaging appearances,
which can be confused with various adnexal masses in
the female pelvis. This complex cystic adnexal mass
can generate a long list of differential diagnoses,
including ovarian cancer, if its characteristic sonographic features are not recognized.
Confident diagnosis of an HOC on the basis of
transvaginal sonography, however, is possible if the
characteristic imaging findings are correlated with the
appropriate clinical setting. The correct diagnosis
allows conservative treatment, avoiding unnecessary
invasive or additional diagnostic procedures and
unnecessary surgery.
The intent of this presentation is to familiarize readers with the most commonly encountered characteristic imaging findings and the imaging spectrum of
hemorrhagic cysts and their differentiation from other
adnexal masses.
© 2002 by the American Institute of Ultrasound in Medicine • J Ultrasound Med 21:879–886, 2002 • 0278-4297/02/$3.50
Sonographic Spectrum of Hemorrhagic Ovarian Cysts
Pathophysiologic Process
The mechanism of development of a hemorrhagic cyst is as follows. The granulosa layer of
the ovary is avascular until ovulation. At the time
of ovulation, as the maturing graafian follicle
enlarges, the immediately surrounding stromal
cells also enlarge and become round and plump.
This change in a stromal cell is called luteinization. The luteinized theca cells become noticeably more vascular than the adjacent stroma.
In response to the midcycle peak of pituitary
luteinizing hormone, the graafian follicle ruptures, expels the oocyte, and rapidly becomes a
corpus luteum. The granulosa layer becomes
vascularized. These vessels within the wall on the
cyst are very fragile and rupture easily, giving rise
to a hemorrhagic cyst.
Cytopathologic examination of an HOC shows
the presence of luteinized granulosa cells, fibroblasts, hemosiderin-laden macrophages, fresh
blood, and abundant fibrin.2 There is no malignant potential in these functional cysts despite
the occurrence of the hemorrhage.
Natural History
In patients with HOCs, the apparent clinical features include pelvic pain and a pelvic mass.
Hemorrhagic ovarian cysts are also found in
asymptomatic patients. The classic history of hemorrhage into an ovarian cyst is the abrupt onset of
pelvic or lower abdominal pain,3 which can wake
the woman from her sleep. Hemorrhagic ovarian
cysts occur almost exclusively in premenopausal
women and in postmenopausal women receiving
hormonal treatment. Although HOCs are not common in early adolescence, they are occasionally
seen in childhood.4 Hemorrhagic cysts tend to
evolve slowly into various stages of acute hemorrhage, clot formation, and clot retraction, thus giving rise to changing sonographic appearances
until they completely resolve. Classically, fresh
blood is anechoic. In subacute stages when the clot
forms, it becomes echogenic. The echogenicity of
the HOC diminishes with time as the red cells
undergo hemolysis. In the initial 24 hours after
hemorrhage, the blood is echogenic, but after this
time its echogenicity decreases so that by 96 hours
it may be entirely echo free.5 Bearing this pathophysiologic process in mind and having familiarity
with the sonographic appearances can enable
definitive diagnosis of a hemorrhagic cyst.
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The last menstrual period should be noted in
premenopausal women, because if the patient is
in the luteal phase and a cyst is seen in the
adnexa with the sonographic appearance of an
HOC, the diagnosis can be made more reliably.
Typical Sonographic Appearance
The average diameter of the cyst is 3.0 to 3.5 cm
(range, 2.5–8.5 cm). The cyst wall is thin (2–3
mm), well defined, and regular. Posterior
enhanced through-transmission is seen, signifying the basic cystic nature of the mass. The internal echo pattern or architecture of the HOC is
best visualized with transvaginal sonography.
Fishnet Weave or Fine Reticular Pattern
A cystic mass is shown in the adnexal region with
posterior enhanced through-transmission. Within
this mass there are fine interdigitating septations,
which give a fishnet weave or fine reticular
appearance (Figs. 1 and 2). Color Doppler sonography shows no flow in these fine septations (Fig.
3), because these are not real tissue septations but
are fibrin strands, which do not contain blood vessels. This is the most common appearance of an
HOC.
Retracting Blood Clot
Another common appearance is a retracting
blood clot. The blood clot may be triangular or
curvilinear and may appear slightly homogeneous or may contain a reticular pattern due to
fibrin strands. The remainder of the cystic mass
appears anechoic, because it contains serum
separated after formation of the clot (Figs. 4
and 5).
Imaging Spectrum
Hemorrhagic Ovarian Cyst With a Fluid-Debris
Level
Occasionally the blood products can separate
into layers, and an HOC can have a fluid-fluid or
fluid-debris level (Fig. 6).
Hemorrhagic Ovarian Cyst Simulating an
Ectopic Pregnancy
Occasionally a hemorrhagic cyst may appear as a
thick echogenic rind surrounding a central anechoic area, an appearance remarkably similar to
that of the adnexal ring, which is widely considered one of the most predictive sonographic
J Ultrasound Med 21:879–886, 2002
Jain
findings of ectopic pregnancy.6 Sometimes the
hemorrhagic cyst may rupture, and there may
be echogenic fluid in the cul-de-sac or surrounding adnexa. When the result of the pregnancy test is positive, these constellations of
findings remarkably simulate a ruptured ectopic
pregnancy (Fig. 7). Also, the other way to differentiate an HOC that simulates an ectopic pregnancy from a bona fide ectopic pregnancy is to
note the location of the cysts. Ectopic pregnancies are extraovarian in location.
Hemorrhagic Ovarian Cyst Simulating an
Ovarian Neoplasm
Hemorrhagic Ovarian Cyst Simulating a Papillary
Cystadenoma
Occasionally the retracting blood clot may
become very small and may simulate a mural
nodule or papilloma (Fig. 8). Color Doppler
sonography would fail to show blood flow in the
clot. This is in contrast to a neoplastic mural
nodule, which typically is vascular.
Figure 1. Transvaginal coronal sonogram from a 23-year-old woman with acute
right-sided pelvic pain showing the typical sonographic appearance of an HOC. A
reticular or fishnet weave pattern in a cystic adnexal mass is shown (calipers).
Hemorrhagic Ovarian Cyst Simulating a Solid Mass
Uncommonly the HOC may appear solid7 on
sonography because of the dense internal
echoes and poor through-transmission (Fig. 9).
This may be seen in the subacute stage, when
there is blood clot formation but the lysis of the
clot has not begun.
Hemorrhagic Ovarian Cyst Simulating a Malignant
Ovarian Neoplasm
A blood clot in a large hemorrhagic cyst may disintegrate such that the areas of a solid clot and
serum together may give an appearance of a
malignant ovarian neoplasm (Fig. 10).
Figure 2. Transvaginal coronal sonogram from a 25-year-old woman with acute
pelvic pain showing another example of a reticular pattern in an HOC. Arrow indicates a retracting blood clot; and arrowheads, fibrin strands.
Ovarian Neoplasm Simulating a Hemorrhagic
Ovarian Cyst
Mucinous Cystadenoma Simulating a Hemorrhagic
Ovarian Cyst
A mucinous cystadenoma can have a reticular
pattern similar in appearance to the reticular
pattern of an HOC (Fig. 11). A small mucinous
cystadenoma and an HOC can sometimes be
confused with each other.
Dermoid Simulating a Hemorrhagic Ovarian Cyst
Occasionally an HOC can have an appearance
similar to that of a benign cystic teratoma.
J Ultrasound Med 21:879–886, 2002
881
Sonographic Spectrum of Hemorrhagic Ovarian Cysts
A
B
Figure 3. Images from a 29-year-old woman with acute pelvic pain. A, Transvaginal right adnexal sonogram showing fine fibrin mesh. The color flow
box shows no evidence of flow in these fibrin strands. B, Septate cyst in the left ovary. Pulsed Doppler sonography shows flow within the septation,
indicating that this is not a fibrin strand.
Figure 4. Sagittal transvaginal sonogram from a 21-year-old woman with an
adnexal mass found on bimanual pelvic examination. A typical retracting clot with
a curvilinear surface (c) is shown, with no evidence of color flow within the mass.
Especially, the echogenic lines produced by the
hair in the dermoid can resemble fibrin strands
(Fig. 12). This can be differentiated by the fact
that the benign cystic teratoma will not change
its echo pattern over a period of days.
Complications of Hemorrhagic Cysts
Rupture of a Hemorrhagic Ovarian Cyst
When a simple ovarian cyst ruptures, anechoic fluid is seen in the pelvis. However when
a hemorrhagic cyst ruptures, echogenic fluid
is seen in the pelvis or may even result in massive hemoperitoneum.8 A ruptured HOC with
hemoperitoneum can have imaging features
similar to those of hemoperitoneum from
other causes.8 Echogenic blood may surround
the uterus and adnexa, and sonographic findings of a ruptured HOC can very closely mimic
a ruptured ectopic pregnancy when a woman
of childbearing age has acute pelvic pain and
hemoperitoneum (Fig. 7). This can become
particularly challenging in the setting of positive pregnancy test results in a very early
intrauterine pregnancy when no intrauterine
pregnancy is visualized. The assertion that a
positive β-human chorionic gonadotropin
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J Ultrasound Med 21:879–886, 2002
Jain
(β-hCG) finding indicates ectopic pregnancy
and a negative β-hCG finding suggests a ruptured hemorrhagic cyst becomes very limiting
in such a situation.8 Coincidental occurrence of
a corpus luteal cyst rupture and an ectopic
pregnancy has been reported.9
Torsion of a Hemorrhagic Ovarian Cyst
Adnexal torsion due to a hemorrhagic cyst is
rarely encountered but has been occasionally
reported.10
Differential Diagnosis of a Hemorrhagic
Ovarian Cyst
Acute onset of pain in the pelvis or lower
abdomen due to an HOC in women closely
mimics other gynecologic conditions such as
ovarian torsion, ectopic pregnancy, and pelvic
inflammatory disease. It can also mimic gastrointestinal disorders such as appendicitis,
mesenteric adenitis, Crohn’s disease, and other
gastrointestinal conditions. Clinical correlation is crucial, because an HOC is unlikely in
the presence of fever and leukocytosis.
In summary, the definitive diagnosis of an
HOC can be made in most cases with the use of
transvaginal sonography in light of an appropriate history and characteristic sonographic
findings. Such patients have abrupt onset of
acute pelvic pain, usually in the midcycle, negative pregnancy test results, and absence of
fever and leukocytosis. Sonography reveals a
cystic mass with good through-transmission
and a fine reticular pattern of fibrin strands,
which do not show blood flow, and it shows a
change in echo pattern with time, which is
related to the temporal sequence of clot formation and lysis. Hemorrhagic ovarian cysts
can be followed to spontaneous resolution
sonographically in 6 to 8 weeks; most completely resolve in 6 weeks or decrease considerably in size and change in morphologic
appearance.
Figure 5. Sagittal transvaginal sonogram from a 19-year-old woman with an
adnexal mass showing another example of a retracting clot with a fine reticular
appearance and no color flow.
recognized. In cases in which the diagnosis of an
HOC cannot be easily made, having the patient
return for follow-up sonography after 1 or 2
cycles between days 5 and 11 in most cases will
clearly facilitate the diagnosis of an HOC.
Figure 6. Transvaginal oblique coronal sonogram from a 31-year-old woman with
pelvic pain showing a retracting clot with a horizontal level and clear serum component, which can be mistaken for a fluid-debris level (arrowheads).
Conclusions
Hemorrhagic ovarian cysts are essentially “nonsurgical” lesions, and in most cases with correct
sonographic diagnosis, conservative treatment
with clinical and sonographic follow-up to resolution is indicated.1 Follow-up sonography is not
necessary if the typical appearance of the HOC is
J Ultrasound Med 21:879–886, 2002
883
Sonographic Spectrum of Hemorrhagic Ovarian Cysts
A
B
Figure 7. Hemorrhagic ovarian cyst simulating a ruptured ectopic pregnancy in a 23-year-old woman with severe acute pelvic pain and a positive β-hCG
finding. A, Coronal right adnexal sonogram showing a mass with an irregular thick rind (arrows). This was mistaken for a ruptured ectopic pregnancy
but was identified as a ruptured hemorrhagic cyst at laparoscopy. The patient had a concurrent very early intrauterine pregnancy. B, Sagittal right adnexal sonogram showing echogenic fluid (arrows) adjacent to the ruptured hemorrhagic cyst (H).
Figure 8. Hemorrhagic ovarian cyst simulating a papillary cystadenoma
in a 29-year-old woman with an adnexal mass and persistent vaginal
bleeding. The transvaginal coronal sonogram shows a small retracted
blood clot, which can be easily mistaken for papilloma, and the lesion
may be misdiagnosed as a papillary cystadenoma.
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Figure 9. Hemorrhagic ovarian cyst simulating a solid mass in a 28-yearold woman with a pelvic mass. The transvaginal sagittal sonogram shows
a left adnexal mass with dense internal echoes. This can be seen when
the blood clot within the cyst is still solid and has not started retraction
and lysis. This was mistaken for a solid mass (M). Normal ovarian
parenchyma with a small follicular cyst is shown (arrow).
J Ultrasound Med 21:879–886, 2002
Jain
Figure 10. Hemorrhagic ovarian cyst simulating a malignant ovarian neoplasm in a 36-year-old woman with an adnexal mass and pelvic pain. The
coronal transvaginal sonogram shows a large mass (arrows) with solid
components and irregular anechoic areas. This was misdiagnosed as a
malignant ovarian neoplasm. However, the solid components represent
the solid portion of a blood clot, and the anechoic areas represent lysing
of the clot. This lesion was completely resolved on follow-up sonography
8 weeks later.
Figure 12. Dermoid cyst simulating an HOC in a 34-year-old woman
with an adnexal mass. The coronal transvaginal sonogram shows an
adnexal mass with poor through-transmission. Multiple echogenic lines
can be mistaken for a reticular pattern of a hemorrhagic cyst; however,
they represent hair in a dermoid cyst.
Figure 11. Mucinous cystadenoma with an architecture similar to that of
an HOC in a 32-year-old woman with abdominal and pelvic pain. The
transabdominal sonogram shows a large pelvic mass with enhanced
through-transmission and a reticular pattern. This was surgically removed
and found to be a mucinous cystadenoma. A small mucinous cystadenoma can be mistaken for an HOC.
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