CYCLE. Ovarian cysts are occasionally pedunculated
(growing on the end of stalks). Such cysts may
twist on their peduncles and become gangrenous,
which is an emergency situation requiring sur-
gery.
Dermoid cysts, also called teratomas or germ
cell cysts, are much less common though more
troublesome because they can grow quite large.
The key characteristic of a dermoid cyst is that it
consists primarily of epithelial tissue though may
also contain fatty tissue and fragments of HAIR,
CARTILAGE, BONE, and sometimes TEETH. Dermoid
cysts are congenital (present from birth). Doctors
do not know how they occur though believe they
arise from cells that escape migration when the
three layers of the early EMBRYO(mesoderm, ecto-
derm, and endoderm) develop.
The doctor detects most ovarian cysts inciden-
tally during routine PELVIC EXAMINATIONor ULTRA-
SOUND of the lower abdomen done for other
reasons. When a woman does have symptoms
they are often nonspecific in nature, such as
abdominal bloating or pressure, CONSTIPATION, URI-
NARY INCONTINENCEorURINARY FREQUENCY, or pain
duringSEXUAL INTERCOURSE(dyspareunia). Abdomi-
nal or transvaginal ultrasound or abdominal COM-
PUTED TOMOGRAPHY (CT) SCAN help the doctor
confirm the diagnosis. When these diagnostic
imaging procedures are not conclusive, the doctor
may perform diagnostic laparoscopy to look at the
cyst and take a tissue sample for biopsy.
Most ovarian cysts go away without treatment
or intervention. The gynecologist may recommend
surgical removal of an ovarian cyst that is large,
persistent, or symptomatic (causes discomfort,
irregular menstrual periods, or bleeding) or when
the cyst has suspicious features that cause the
gynecologist to want to rule out OVARIAN CANCER.
Though ovarian cysts are not cancerous and very
seldom become cancerous, they can co-exist with
cancerous tumors. As well, ovarian cancer tumors
commonly have cystic characteristics. Often it is
possible to remove the cyst without damaging the
ovary. When the cyst is large or questionable the
surgeon may need to remove the entire ovary
(OOPHORECTOMY). As long as the remaining ovary is
healthy and functional, removing a single ovary
does not affect the menstrual cycle or FERTILITY.
See also OVARIES; SURGERY BENEFIT AND RISK
ASSESSMENT.ovaries The female organs of reproduction, also
called the female gonads. The ovaries produce OVA
(eggs) and sex hormones, predominantly ESTRO-
GENSand PROGESTERONEas well as small amounts of
ANDROGENS. A woman has two ovaries, one ovary
on each side of the UTERUSin the lower abdomen.
Ligaments suspend the ovaries in place within the
abdominal cavity. Each ovary is about the size,
shape, and consistency of a large olive. At birth it
contains the full complement of ova that will sup-
ply a woman for all her years of FERTILITY.
The ovary has two distinct layers of structure,
an outer cortex and an inner medulla. The ovar-
ian cortex contains the ovarian follicles, each of
which holds an immature ovum (egg), also called
a GAMETEor germ cell. The fibrous tissue of the
ovarian medulla, made up of stroma cells, con-
tains the ovary’s BLOODvessels, LY M P Hvessels, and
nerves. The layer of cells covering the ovary is the
epithelium; it is made up of epithelial cells (the
same type of cell that makes up the SKINand
mucous membranes throughout the body).
Beginning during PUBERTY with the onset of
MENSTRUATION, hormonal influences ripen one
ovum (sometimes called an oocyte) each MEN-
STRUAL CYCLE. The ovary releases the ovum into a
pocket of fluid that surrounds it. The fimbriae of
the fallopian tube (fluted edges of the tube’s open
end) float in this fluid, extending toward but not
touching the ovary. The undulating movements of
the fimbriae pull the released ovum into the fal-
lopian tube where, if SPERMare also present, fertil-
ization may occur.
The PITUITARY GLANDreleases FOLLICLE-STIMULAT-
ING HORMONE(FSH) and LUTEINIZING HORMONE(LH) at
different phases of the menstrual cycle to stimu-
late the sequence of events that will cause the
maturation of an ovum. Several ova typically
begin the maturation process during each men-
strual cycle though usually only one will complete
it. The follicle expels the mature, or ripe, ovum.
The cells of the follicle produce estrogens and pro-
teins. The developing ovum is a haploid cell—that
is, is contains precisely one half the complement
of chromosomes (23) necessary to support humanovaries 313