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A teratoma is a type of germ
cell tumor which contains several different types of cells, caused
when germ cells run amok and start replicating where they
shouldn't. This type of tumor is actually present at birth, but it
may not be noticed until later in life, and it could be considered
a form of congenital birth defect. Most teratomas are benign, but
some can become malignant, especially if they are located in the
testes.
The word “teratoma” literally means “monstrous tumor” in Greek, a
reference to the jumbled mass of tissue types which is common to
teratomas. They can contain skin, hair, bone, and cells like those
found in various organs and glands. In some cases, structures such
as eyes and extremities have developed. Teratomas can be found
anywhere in the body, and in some cases, the tumor may even be
visible during ultrasound examinations, in which case it may be
possible to remove the tumor before birth.
To be considered a true teratoma, the tumor must contain all three
layers of the germ cells. Germ cells are very unique because they
can divide and differentiate into anything, from the upper layers
of the skin to the internal organs of the body. In the case of a
teratoma, a pocket of germ cells starts to multiply, and several
different types of tissue begin to develop, but the tissue is
usually not functional.
Historically, teratomas were a topic of intense interest.
Especially large teratomas or growths with unusual complexity were
preserved in anatomical collections as examples of curiosities,
and the opportunity to see or operate on a teratoma was exciting
for many medical practitioners. Now that we know how teratomas
form, these tumors are much less mysterious, but they can still be
rather interesting.
Teratomas can grow quite rapidly, and they may cause a variety of
symptoms, depending on where they are located. Benign tumors can
cause inflammation, abdominal pressure, and obvious swellings,
while malignant tumors can start to spread to neighboring organs,
causing a decline in organ function.
what
Age group are affected?
The presenting location of teratomas correlates with age.
* In infancy and early childhood, the most frequent location is
extragonadal, whereas teratomas presenting after childhood more
commonly are located in the gonads.[25]
* An increasing number of patients with sacrococcygeal teratomas
are diagnosed antenatally. In Gabra’s series this proportion
increased from 11% before 1988 to 53% from 1988-2001. The majority
of sacrococcygeal teratomas are diagnosed in the neonatal period.
Patients presenting later tend to have less obvious external
tumors and symptoms of bladder or bowel dysfunction often leads to
diagnosis.
* Cystic teratomas of the ovary can occur in persons of any age,
although they are diagnosed most frequently during the
reproductive years. The peak incidence in most series is age 20-40
years.[18]
*Testicular teratomas may occur at any age but are more common in
infants and children. In adults, pure testicular teratomas are
rare, constituting 2-3% of germ cell tumors.[22]
* Mediastinal teratomas can be found in persons of any age but
occur most commonly in adults aged 20-40 years.
Sex
ratio
Sacrococcygeal teratomas are much more common in females than in
males, occurring in a female-to-male ratio of approximately 3-4:1.
Most sources report no sex predilection for mediastinal teratomas.
Others document a marked male or marked female predominance.
Excluding testicular teratomas, 75-80% of teratomas occur in
girls.
Sacrococcygeal teratoma
Sacrococcygeal teratomas are commonly diagnosed in the prenatal
period, and complications may occur in uterus or during or after
birth. The outcome after antenatal diagnosis is significantly
worse than that for older postnatal surgical series, with survival
rates ranging from –54-77%.
Potential complications in uterus include polyhydramnios and
tumours hemorrhages, which can lead to anemia and non immune
hydrops fetalis. If significant atrioventricular shunting occurs
within the tumour, hydrops may result from high-output cardiac
failure. Development of hydrops is an ominous sign. If it develops
after 30 weeks' gestation, the mortality rate is 25%. If it is
recognized, delivery is recommended as soon as lung maturity is
documented. Development of hydrops before 30 weeks' gestation has
an abysmal prognosis, with a 93% mortality rate. Make in et al
reported that antenatal intervention for the treatment of fetal
hydrops did not improve outcomes with neonatal deaths in 6 (86%)
of 7 cases. Hydrops and prematurely are the two main factors that
contribute to mortality.
Postpartum morbidity associated with sacrococcygeal teratomas is
attributable to associated congenital anomalies, mass effects of
the tumor, recurrence, and intraoperative and postoperative
complications. Ten to twenty-four percent of sacrococcygeal
teratomas are associated with other congenital anomalies,
primarily defects of the hindgut and cloacal region, which exceeds
the baseline rate of 2.5% expected in the general population.
In one larger series that included 57 cases of benign teratomas
over a 40-year period from a single institution, 5 recurrences
were documented. Only one of the patients who experienced
recurrence did not undergo a coccygectomy, and one patient who was
thought to have a benign tumor with immature elements was found to
have embryonal carcinoma after the third excision. In this same
series, 3 patients had postoperative wound infections and one
patient had postoperative pneumonia. The overall survival was 95%
and morbidity or mortality rates were consistent over the 40-year
period of the study.
In a more recent series, all 26 patients diagnosed with benign
teratomas survived. Seven of 20 patients with long-term follow-up
developed neuropathy bladder or bowel disturbances. A longitudinal
cross-sectional follow-up study found that squeal developing in
childhood tended to improve with time, while functional symptoms
reported in adulthood were common in the general population and
not significantly increased over a control group.
Ovarian
teratoma
Complications of ovarian teratomas include torsion, rupture,
infection, hemolytic anemia, and malignant degeneration.
Torsion is by far the most significant cause of morbidity,
occurring in –3-11% of cases. Several series have demonstrated
that increasing tumor size correlates with increased risk of
torsion.
Rupture of a cystic teratoma is rare and may be spontaneous or
associated with torsion. Most series report a rate of less than
1%,though Ahan et al reported a rate of 2.5% in their report of
501 patients.[18] Rupture may occur suddenly, leading to shock or
hemorrhage with acute chemical peritonitis. Chronic leakage also
may occur, with resultant granulomatous peritonitis. Prognosis
after rupture is usually favorable, but the rupture often results
in formation of dense adhesions.
Infection is uncommon and occurs in less than 1-2% of cases.
Coliform bacteria are the organisms most commonly implicated.
Autoimmune hemolytic anemia has been associated with mature cystic
teratomas in rare cases. In these reports, removal of the tumor
resulted in complete resolution of symptoms. Theories behind the
pathogenetic mechanism include (1) tumor substances that are
antigenically different from the host and produce an antibody
response within the host that cross reacts with native red blood
cells, (2) antibody production by the tumor directed against host
red blood cells, and (3) coating of the red blood cells by tumor
substance that changes red blood cell antigenicity. In this
context, radiologic imaging of the pelvis may be indicated in
cases of refractory hemolytic anemia.
In its pure form, mature cystic teratoma of the ovary is always
benign, but in approximately 0.2-2% of cases, it may undergo
malignant transformation into one of its elements, the majority of
which are squamous cell carcinomas. The prognosis for patients
with malignant degeneration is generally poor but dependent on
stage and degenerated cell type.
Testicular teratoma
Testicular teratomas occur in children and adults, but their
incidence and natural history contrast sharply. Pure teratomas
comprise 38% of germ cell tumors in infants and children but only
3% after puberty. In children, they behave as a benign tumor,
whereas in adults and adolescents they are known to metastasize.
With no documented cases of metastasis, morbidity from prepubertal
testicular teratomas is largely limited to surgical or
postoperative complications.
During and after puberty, all teratomas are regarded as malignant
because even mature teratomas (composed of entirely mature
histologic elements) can metastasize to retroperitoneal lymph
nodes or to other systems. Rates reported vary from 29-76%.
Morbidity is associated with growth of the tumor, which may invade
or obstruct local structures and become unresectable.
Approximately 20% of patients relapse during surveillance.
Mediastinal teratoma
Mature teratomas of the mediastinum, the most common mediastinal
germ cell tumor, are benign lesions. They do not have the
metastasis potential observed in testicular teratoma and are cured
by surgical resection alone. Because of their anatomic location,
intraoperative and postoperative complications are the only
significant source of morbidity, as other intrathoracic structures
are often intimately involved with the tumor.
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