INTRODUCTION
A 21-year-old nulliparous woman complains of lower abdominal "heaviness." She takes an oral contraceptive and is in a monogamous relationship. On examination, she has a normal-sized, nontender uterus, and a 9-cm right adnexal mass is palpated. Her pregnancy test is negative. On sonography, the mass appears cystic and solid.
· What is the most likely
diagnosis?
· What are some of the
histologic findings expected in this mass?
Summary: A 21-year-old nulliparous woman has a
9-cm right adnexal mass that on sonography appears cystic and
solid.
· Most likely diagnosis:
Benign cystic teratoma of the ovary.
· Expected histologic
findings in this mass: Any tissue may be found, but the most common are
sebum, skin, hair, teeth, thyroid, and neurologic tissues.
CLINICAL
CORRELATION
Introduction
This young woman has an ovarian mass that on ultrasound
has cystic and solid components, a classic presentation of a benign cystic
teratoma (dermoid cyst) of the ovary. Although benign cystic teratomas are often
asymptomatic, larger dermoids (as in this case) can present with pelvic pain,
pressure, fullness, or dyspareunia. The patient's pregnancy test was reported as
negative; however, in rare cases, degenerating ectopic pregnancies can be missed
with urine human chorionic gonadotropin (hCG) assays because of the low
sensitivity of urine pregnancy tests in the presence of very low (<25 mIU/mL) serum hCG levels. The fact that the patient is
engaged in a monogamous relationship should decrease the risks of her
contracting gonorrhea or Chlamydia, hence decreasing the possibility of
pelvic inflammatory disease and tuboovarian abscess (TOA). The patient also
gives a history of oral contraceptive (OC) use, which also serves to decrease
the risk of pelvic inflammatory disease and/or TOA. Oral contraceptives also
greatly decrease the likelihood of the mass being a physiologic ovarian mass
(follicular cyst, hemorrhagic corpus luteum cyst, etc.). The ultrasound shows a
complex (both cystic and solid) ovarian mass, which also is not consistent with
an abscess or a physiologic ovarian or paraovarian cyst.
Although some disagreement exists over the timing and
indications for surgery in complex masses under 6 cm or simple cysts of any
size, a 9-cm complex ovarian mass almost always needs to be explored surgically.
This is due primarily to the small but not insignificant risk of malignancy.
Upon confirmation of benign intraoperative findings, efforts should be directed
at salvaging all normal tissue from the affected ovary and removing only that
tissue which has undergone neoplastic degeneration.
Approach to
Ovarian Neoplasm
Definitions
Tuboovarian abscess: An abscess formed within
the adnexal space consisting of ovary, fallopian tube, and matted bowel caused
by untreated or inadequately treated pelvic inflammatory disease.
Endometrioma: A large (6- to 8-cm) loculated
collection of endometrial tissue that can develop in the pelvis in females with
endometriosis. As this tissue degenerates, it turns brownish in color and is
known as a chocolate cyst.
Struma ovarii: A benign teratoma in which
functional thyroid tissue is the predominant histologic finding. Approximately 2
to 3 percent of teratomas are classified as struma ovarii. Thyrotoxicosis is
clinically apparent in 5 percent of these cases.
Ovarian torsion: A condition in which the ovary
twists on its attachment to the infundibulopelvic ligament, thus interrupting
ovarian blood supply. This usually is seen in conjunction with pathologic
enlargement of the ovary and can be dynamic (intermittent) in nature or
complete; the latter results in infarction and necrosis of the affected
ovary.
| Table 10-1. DIFFERENTIAL DIAGNOSES OF A PELVIC MASS |
| Full bladder |
| Intrauterine or extrauterine pregnancy |
| Functional ovarian cysts (follicular or corpus luteum) |
| Tuboovarian abscess |
| Diverticular abscess |
| Appendiceal abscess |
| Matted bowel and/or omentum |
| Paratubal or paraovarian cyst |
| Stool in sigmoid colon |
| Leiomyomas (submucosal, subserosal, pedunculated, or intraligamentous) |
| Pelvic kidney |
| Mullerian abnormality (e.g., bicornuate uterus) |
| Benign or malignant ovarian tumors |
Discussion
Although they may present in any decade of life,
benign cystic teratomas are the most common ovarian neoplasm found in
females under age 35 (excluding physiologic follicular and corpus luteum cysts)
and are also the most common ovarian neoplasm found in pregnancy. Approximately
10 to 15 percent of all cases involve both ovaries. Table
10-1 lists the differential diagnoses of a pelvic mass, and Table
10-2 lists the categories of ovarian neoplasms.
| Table 10-2. OVARIAN NEOPLASMS | |
Benign epithelial ovarian
tumors
| |
Serous
cystadenoma
| |
Mucinous
cystadenoma
| |
Brenner
tumor
| |
Malignant epithelial
ovarian tumors
| |
Serous
cystadenocartcinoma
| |
Mucinous
cystadenocarcinoma
| |
Endometroid
adenocarcinoma
| |
Transitional cell
carcinoma
| |
Malignant germ cell
tumors
| |
Dysgerminoma
| |
Endodermal sinus
tumor
| |
Embryonal
carcinoma
| |
Polyembryonal
carcinoma
| |
Choriocarcinoma
| |
Teratoma
(immature)
| |
Benign germ cell
tumors
| |
Benign cystic teratoma
(dermoid)
| |
Sex cord-stromal
tumors
| |
Thecoma
| |
Sertoli-Leydig cell
tumor
| |
Granulosa-theca cell
tumor
| |
Benign cystic teratomas arise from a single germ cell
in the ovary and have a normal female karyotype (46,XX). Because of the
pleuripotent nature of germ cells, teratomas can differentiate into tissues
derived from all three embryologic cell lines (endoderm, ectoderm, and
mesoderm). Thus, a "mature" teratoma often contains skin, fat,
sebaceous glands, sweat glands, hair, smooth and striated muscle, cartilage,
bone, teeth, neural tissue, and gastrointestinal tissue (see Figure 10-1).
Functional thyroid tissue is found in approximately 12 percent of benign
cystic teratomas, and rarely this tissue will proliferate into the predominant
cellular element in the teratoma. This unique teratoma hence is referred to as
struma ovarii and will secrete enough functional thyroid hormone to cause acute
thyrotoxicosis in approximately 5 percent of cases.
Benign cystic teratomas are usually asymptomatic and
are found most commonly during routine gynecologic screening or incidentally
during unassociated surgical or radiographic procedures. Larger teratomas give
rise to acute adnexal torsion in approximately 11 percent of cases. The
increased risk of torsion with teratomas compared with other causes of ovarian
enlargement is thought to be due to fat content, allowing the teratoma to
"float" in the abdominal cavity instead of lodging against other structures.
Other significant complications include secondary infection and acute hemorrhage
with the potential for septic and/or hypovolemic shock. Rupture or perforation
is seen in less than 5 percent of cases and occurs more frequently in
association with pregnancy. When acute rupture occurs, spillage of the contents
of the teratoma into the abdominal cavity often precipitates a surgical
emergency, whereas more chronic leakage of contents can produce a severe
chemical peritonitis that also requires surgical intervention. Malignant
degeneration occurs in less than 2 percent of all recognized
teratomas.
Other germ cell tumors include dysgerminomas,
endodermal sinus tumors, and choriocarcinomas. These neoplasms usually occur in
females under age 30 years. Dysgerminomas are rapidly growing and very
radiosensitive and chemosensitive. Endodermal sinus tumors often secrete
alpha-fetoprotein, whereas choriocarcinomas secrete human chorionic
gonadotropin.
Epithelial tumors of the ovary most commonly
affect females over age 30 years, particularly postmenopausal women.
Malignant serous cystadenocarcinomas are the most common, usually
presenting with ascites. Treatment includes surgical excision followed by
combination chemotherapy. Mucinous tumors may become very large,
sometimes exceeding 30 pounds in weight; their rupture can lead to chronic bouts
of bowel obstruction (pseudomyxoma peritonei).
Stromal tumors of the ovary are often
functional, secreting estrogen (granulosa-theca cell tumors) or androgens
(Sertoli-Leydig cell tumors). These neoplasms can present as precocious
puberty, postmenopausal bleeding, or hirsutism. They are usually solid tumors
that are slow growing and rarely metastasize early. Surgery is the best
treatment for these tumors.
COMPREHENSION
QUESTIONS
[10.1] A 58-year-old woman is noted to have bilateral
adnexal masses on physical examination. Which of the following is most
suggestive of these adnexal masses being malignant?
A. CT imaging revealing that they are primarily
cystic
B. Elevation of the serum alkyline phosphatase
level
C. Family history of lung cancer
D. The presence of ascites
E. The presence of low-grade fever
[10.2] A 25-year-old woman is noted to have a solid and
cystic right ovarian mass measuring 10 cm on ultrasound. Which of the following
is the most likely histologic subtype?
A. Serous
B. Mucinous
C. Brenner
D. Teratoma
E. Fibroma
[10.3] A 4-year-old girl is noted to have breast
enlargement and vaginal bleeding. On physical examination, she is noted to have
a 9-cm pelvic mass. Which of the following is the most likely
etiology?
A. Cystic teratoma
B. Dysgerminoma
C. Endodermal sinus tumor
D. Granulosa cell tumor
E. Mucinous tumor
[10.4] A 44-year-old woman undergoes an exploratory
lapartomy for suspected ovarian cancer. Upon removal of the right ovary, a
frozen section reveals "signet ring" cells. Which of the following is the most
likely etiology?
A. Dysgerminoma
B. Metastatic
C. Mucinous
D. Serous
E. Teratoma
ANSWERS
[10.1] D. The presence of ascites and ovarian
masses is strongly associated with ovarian cancer. Other features of malignancy
include solid ovarian masses, bilaterality, and lymphadenopathy.
[10.2] D. The benign cystic teratoma or dermoid
cyst is the most common type of ovarian tumor in females younger than age 30
years. Dermoid cysts usually have solid and cystic components.
[10.3] D. This young girl has signs of
precocious puberty. Thus, the adnexal mass is likely to be an estrogen-secreting
granulosa-theca cell tumor. These low-grade malignancies are slow-growing
so-called stromal cell tumors. The androgen-secreting tumors are usually
Sertoli-Leydig cell tumors and may cause virilism.
[10.4] B. Signet ring cells suggest a Krukenberg
tumor, usually metastatic from the gastrointestinal tract (stomach, colon) or
breast. The mucin that fills the cell pushes the nucleus to the periphery of the
cell, leading to the appearance of a signet ring.
PATHOLOGY
PEARLS
· Benign cystic teratomas are
the most common nonphysiologic ovarian tumor in females under age 35.
· Ten to 15 percent of all
teratomas are bilateral.
· Ovarian torsion occurs
frequently with teratomas.
· The most common ovarian
cancers are epithelial in origin and usually occur in postmenopausal women.
Surgical excision followed by combination chemotherapy is the best
treatment.
· Ovarian cancer is
associated with ascites.
· Granulosa-theca cell tumors
often secrete estrogen, and Sertoli-Leydig cell tumors often secrete
androgens.
· Metastatic tumors to the
ovary may have a "signet ring" appearance on microscopy and are called
Krukenberg tumors.
REFERENCES
Crum CP. The female genital tract: The
gastrointestinal tract. In: Kumar V, Assas AK, Fausto N, eds. Robbins and Cotran
pathologic basis of disease, 7th ed. Philadelphia: Elsevier Saunders,
2004:1092-1104.
Novak E, Hillard PA, Berek J. Novak's gynecology, 13th
ed. Philadelphia: Lippincott Williams & Wilkins,
2002.
Stenchever MA, Droegmueller W, Herbst HR, Mishell D.
Comprehensive gynecology, 4th ed. Philadelphia: Mosby, 2002.
Copyright © 2006 by the
McGraw-Hill Companies, Inc. All rights reserved.
