UTERINE FIBROID
Fibroid is the commonest benign tumor of the
uterus and also the commonest benign solid tumor
in female. Histologically, this tumor is composed
of smooth muscle and fibrous connective tissue, so
named as uterine leiomyoma, myoma or fibromyoma.
Incidence
It has been estimated that at least
20 percent of women at the age of
30 have got fibroid in their wombs.
Fortunately, most of them (50%) remain asymptomatic.
The incidence of symptomatic fibroid in hospital
outpatient is about 3 percent. A high incidence of 10
percent prevails in England. In colored races (black
women), the incidence is even higher.
Histogenesis
Origin
The etiology still remains unclear. The prevailing
hypothesis is that, it arises from the neoplastic single
smooth muscle cell of the myometrium. The stimulus
for initial neoplastic transformation is not known. The
following are implicated:
™ Chromosomal abnormality—In about 40 percent
of cases, there is a varying type of chromosomal
abnormality, particularly the chromosome six or seven
(rearrangements, deletions). Somatic mutations in
myometrial cells may also be the cause for uncontrolled
cell proliferation.
™ Role of polypeptide growth factors—Epidermal
growth factor (EGF), insulin-like growth factor-1
transforming growth factor (TGF), stimulate the growth
of leiomyoma either directly or via estrogen.
™ A positive family history is often present.
Growth
It is predominantly an estrogen-dependent tumor.
Estrogen and progesterone is incriminated as the
cause. Estrogen dependency is evidenced by:
™ Growth potentiality is limited during childbearing
period.
™ Increased growth during pregnancy.
™ They do not occur before menarche.
™ Following menopause, there is cessation of growth
and there is no new growth at all.
™ It seems to contain more estrogen receptors than
the adjacent myometrium.
™ Frequent association of anovulation.
BODY OR CORPOREAL FIBROIDS
Pathology
Naked eye appearance
The uterus is enlarged; the shape is distorted by
multiple nodular growth of varying sizes. Occasionally,
there may be uniform enlargement of the uterus by a
single fibroid. The feel is firm (Fig. 19.3).
Cut surface of the tumor is smooth and whitish.
The cut section, in the absence of degenerative
changes, shows features of whorled appearance and
trabeculation. These are due to the intermingling of
fibrous tissues with the muscle bundles.
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The false capsule is formed by
the compressed adjacent myometrium. They have
more parallel arrangement and are pinkish in color
in contrast to whitish appearance of the tumor. The
capsule is separated from the growth by a thin loose
areolar tissue. The blood vessels run through this
plane to supply the tumor. It is through this plane
that the tumor is shelled out during myomectomy
operation. The periphery of the tumor is more
vascular and have more growth potentiality. The
center of the tumor is least vascular and likely
to degenerate. It is due to contraction of the false
capsule that makes the cut surface of the tumor to bulge out.
SECONDARY CHANGES IN FIBROIDS
™ Degenerations
™ Atrophy
™ Necrosis
™ Infection
™ Vascular changes
™ Sarcomatous change
Microscopic views of uterine fibroid Degenerations
Hyaline degeneration is the most common (65%)
type of degeneration affecting all sizes of fibroids
except the tiny one. It is common specially in tumors
having more connective tissues. The central part of
the tumor which is least vascular is the common site.
The feel becomes soft elastic in contrast to firm feel
of the tumor.
Naked eye examination on the cut surface shows
irregular homogenous areas with loss of whorl-like
appearance.
Microscopic examination reveals hyaline changes
of both the muscles and fibrous tissues.
Cystic degeneration usually occurs following
menopause and is common in interstitial fibroids. It
is formed by liquefaction of the areas with hyaline
changes. The cystic spaces are lined by irregular ragged
walls. The cystic changes of an isolated big fibroid may
be confused with an ovarian cyst or pregnancy.
Fatty degeneration is usually found at or after
menopause. Fat globules are deposited mainly in the
muscle cells.
Calcific degeneration (10%) usually involves the
subserous fibroids with small pedicle or myomas of
postmenopausal women. It is usually preceded by
fatty degeneration. There is precipitation of calcium
carbonate or phosphate within the tumor. When whole
of the tumor is converted into a calcified mass, it is
called “womb stone”
Red degeneration (carneous degeneration) occurs in
a large fibroid mainly during second half of pregnancy
and puerperium. Partial recovery is possible and as
such called necrobiosis. The cause is not known but
is probably vascular in origin. Infection does not play
any part.
Complications of fibroids
™ Degenerations
™ Necrosis
™ Infection
™ Sarcomatous change (rare)
™ Torsion of subserous pedunculated fibroid
™ Hemorrhage
– Intracapsular
– Ruptured surface vein of subserous fibroid →
intraperitoneal
™ Polycythemia due to
– Erythropoietic function by the tumor
– Altered erythropoietic function of the kidney
through ureteric pressure
CLINICAL FEATURES
Patient Profile
The patients are usually nulliparous or having long
period of secondary infertility. However, early
marriage and frequent childbirth make its frequency
high even amongst the multiparous women. The
incidence is at its peak between 35–45 years. There
is a tendency of delayed menopause.
Symptoms: The majority of fibroids remain
asymptomatic (75%). They are accidentally discovered
by the physician during routine examination or at
laparotomy or laparoscopy.
The symptoms are related to anatomic type and size
of the tumor. The site is more important than the
size. A small submucous fibroid may produce more
symptoms than a big subserous fibroid.
™ Pelvic congestion.
™ Role of prostanoids—imbalance of throm-
boxane (TXA2
) and prostacyclin (PGI2
) with
relative deficiency of TXA2
(b) Metrorrhagia or irregular bleeding may be
due to:
™ Ulceration of submucous fibroid or fibroid
polyp.
™ Torn vessels from the sloughing base of a polyp.
™ Associated endometrial carcinoma.
Dysmenorrhea: The congestive variety may be due
to associated pelvic congestion or endometriosis.
Spasmodic type is associated with extrusion of polyp
and its expulsion from the uterine cavity.
Subserous, broad ligament or cervical fibroids are
usually unassociated with menstrual abnormalities.
Infertility: Infertility (30%) may be a major complaint.
The probable known attributing factors are:
Uterine
Distortion and or elongation of the uterine
cavity → difficult sperm ascent.
Preventing rhythmic uterine contraction due to
fibroids during intercourse → impaired sperm
transport.
Congestion and dilatation of the endometrial
venous plexuses → defective nidation.
Atrophy and ulceration of the endometrium over
the submucous fibroids → defective nidation.
Menorrhagia and dyspareunia.
(a) Menorrhagia (30%) is the classic symptom of
symptomatic fibroid.
The menstrual loss is progressively increased with
successive cycles. It is conspicuous in submucous
or interstitial fibroids. The causes are:
™ Increased surface area of the endometrium
(Normal is about 15 sq cm).
™ Interference with normal uterine contractility
due to interposition of fibroid.
™ Congestion and dilatation of the subjacent
endometrial venous plexuses caused by the
obstruction of the tumor.
™ Endometrial hyperplasia due to hyperestrinism
(anovulation).
™ Pelvic congestion.
™ Role of prostanoids—imbalance of throm-
boxane (TXA2
) and prostacyclin (PGI2
) with
relative deficiency of TXA2
.
(b) Metrorrhagia or irregular bleeding may be
due to:
™ Ulceration of submucous fibroid or fibroid
polyp.
™ Torn vessels from the sloughing base of a polyp.
™ Associated endometrial carcinoma.
Dysmenorrhea: The congestive variety may be due
to associated pelvic congestion or endometriosis.
Spasmodic type is associated with extrusion of polyp
and its expulsion from the uterine cavity.
Subserous, broad ligament or cervical fibroids are
usually unassociated with menstrual abnormalities.
Infertility: Infertility (30%) may be a major complaint.
The probable known attributing factors are:
Tubal
Cornual block due to position of the fibroid.
Marked elongation of the tube over a big fibroid.
Associated salpingitis with tubal block.
Ovarian: Anovulation
Peritoneal: Endometriosis
Unknown—(majority)
Pregnancy-related problems like abortion, preterm
labor and intrauterine growth restriction are high. The
reasons are defective implantation of the placenta,
poorly developed endometrium, reduced space for
the growing fetus and placenta. Red degeneration and
torsion of subserous pedunculated fibroid is common
in pregnancy. Labor dystocia, postpartum hemorrhage
are also more.
Pain lower abdomen
The fibroids are usually painless. Pain may be due to
some complications of the tumor or due to associated
pelvic pathology.
Due to tumor
Degeneration
Torsion subserous pedunculated fibroid
Extrusion of polyp.
Associated pathology
Endometriosis
PID
Abdominal swellings (lump)
The patient may have a sense of heaviness in lower
abdomen. She may feel a lump in the lower abdomen
even without any other symptom.
Ultrasonographic view of uterine fibroid
Abdominal examination
The tumor may not be sufficiently enlarged to be felt
per abdomen. But if enlarged to 14 weeks or more,
the following features are noted.
Palpation
Feel is firm, more toward hard; may be cystic in
cystic degeneration.
Margins are well-defined except the lower pole
which cannot be reached suggestive of pelvic in
origin.
Surface is nodular; may be uniformly enlarged in
a single fibroid.
Mobility is restricted from above downwards but
can be moved from side to side.
Percussion
The swelling is dull on percussion.
Pelvic examination
Bimanual examination reveals the uterus irregularly
enlarged by the swelling felt per abdomen. That the
swelling is uterine is evidenced by:
Uterus is not felt separated from the swelling and
as such a groove is not felt between the uterus and
the mass
The cervix moves with the movement of the tumor
felt per abdomen.
INVESTIGATIONS
The investigations aim at:
To confirm the diagnosis
Preoperative assessment
To confirm the diagnosis
- Ultrasound and Color Doppler (TVS) findings
are:
- Saline Infusion Sonography (SIS)
- Magnetic resonance imaging (MRI)
- Laparoscopy
- Hysteroscopy
Preoperative assessment: Apart from routine
preoperative investigations, intravenous pyelography
to note the anatomic changes of the ureter may be
helpful
Differential diagnosis: The fibroid of varying sizes
may be confused with: (1) Pregnancy (2) Full bladder
(3) Adenomyosis (4) Myohyperplasia (5) Ovarian
tumor (6) TO mass.
MANAGEMENT OF FIBROID UTERUS
(1) MEDICAL MANAGEMENT
™ To improve menorrhagia and to correct anemia
before surgery.
™ To minimize the size and vascularity of the tumor
in order to facilitate surgery.
™ In selected cases of infertility to facilitate
hysteroscopic or laparoscopic surgery
™ As an alternative to surgery in perimenopausal
women or women with high-risk factors for surgery.
™ Where postponement of surgery is planned
temporarily.
To minimize blood loss
Antiprogesterones (p. 537)—Mifepristone (RU
486) is very effective to reduce fibroid size and also
menorrhagia. It may produce amenorrhea. It reduces
the size of the fibroid significantly. A daily dose
of 25–30 mg is recommended for 3 months. 5 mg
daily dose is also found effective. Long-term therapy
is avoided as it causes endometrial hyperplasia.
Asoprisnil is used with success. It is a selective
progesterone receptor modulator. It does not cause
endometrial hyperplasia.
Danazol (p. 530)—can reduce the volume of a fibroid
slightly. Because of androgenic side effects, danazol
is used only for a period of 3–6 months. Danazol
administered daily in divided doses ranging from
200-400 mg for 3 months minimizes blood loss or
even produce amenorrhea by its antigonadotropin and
androgen agonist actions.
GnRH agonists (p. 525)—Drugs commonly used are
goserelin, luporelin, buserelin or nafarelin (see p. 525).
Mechanism of action is sustained pituitary down
regulation and suppression of ovarian function.
Optimal duration of therapy is 3 months. Addback
therapy may be needed to combat hypestrogenic
symptoms (see p. 527).
GnRH antagonists (p. 527)—Cetrorelix or ganirelix
causes immediate suppression of pituitary and the
ovaries. They do not have the initial stimulatory effect.
Benefits are same as that of agonists (see Table 19.8).
Onset of amenorrhea is rapid.
Prostaglandin synthetase inhibitors—These are used
to relieve pain due to associated endometriosis or
degeneration of the fibroid. They cannot improve
menorrhagia due to fibroids.
Levonorgestrel-releasing Intrauterine System
(LNG-IUS) reduces blood loss and uterine size.
However, this is not recommended when the uterine
size is >12 weeks or there is distortion of uterine
cavity.
Preoperative therapy: It is indeed advantageous to
reduce the size and vascularity of fibroid prior to either
myomectomy or hysterectomy. While operation will
be technically easier in broad ligament or cervical
fibroid, in myomectomy, there may be little difficulty
in enucleation of the tumor from its pseudocapsule.
SURGICAL MANAGEMENT
OF FIBROID UTERUS
■ Myomectomy
(may be done by)
Laparotomy
Laparoscopy
Hysteroscopy
■ Embolotherapy
= Myolysis
= Hysterectomy
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