Teratoma, Cystic


Background: Teratomas are tumors in which more than a single cell type is derived from more than one germ layer. There has been a significant degree of confusion regarding nomenclature for the various subtypes of teratomas. The word itself is derived from the Greek word teraton, meaning monster, and was used initially by Virchow in the first edition of his book on tumors, which was published in 1863. Teratomas range from benign, well-differentiated (mature) cystic lesions to those that are solid and malignant (immature). Monodermal and highly specialized teratomas, as well as mature teratomas with malignant transformation also occur.

The term dermoid cyst was coined in the veterinary literature in 1831 by Leblanc when he removed a lesion that resembled skin at the base of a horse’s skull, which he called a kyste dermoid. Both terms, now more than a century old, still are in general use and often are used interchangeably. The earliest implications were that dermoids were composed predominantly of elements similar to skin and its appendages, while teratomas had no such limits. It is now recognized that dermoids are indeed often trigeminal and may contain practically any type of tissue. In those who continue to make a distinction, dermoids are tumors that maintain rather orderly arrangements, with well-differentiated ectodermal and mesodermal tissues surrounding endodermal components. Teratomas, specifically solid teratomas, essentially are devoid of organization; thus, the presence of some degree of organization, a high degree of cellular differentiation, and cystic structure differentiate dermoids from teratomas. This article focuses onmaturecystic teratomas, commonly referred to as dermoid cysts.


Pathophysiology: Teratomas are made up of a variety of parenchymal cell types representative of more than a single germ layer, usually all 3. Arising from totipotential cells, these tumors typically are midline or para-axial. The most common location is sacrococcygeal (57%). Because they arise from totipotential cells, they are commonly encountered in the gonads (29%). By far the most common gonadal location is the ovary, although they also occur somewhat less frequently in the testes. Cystic teratomas occasionally occur in sequestered midline embryonic cell rests and can be mediastinal (7%), retroperitoneal (4%), cervical (3%), and intracranial (3%). Cells differentiate along various germ lines, essentially recapitulating any tissue of the body. Examples include hair, teeth, fat, skin, muscle, and endocrine tissue.



Mortality/Morbidity: Mature cystic teratomas can result in significant morbidity. Potential complications vary depending on the site of occurrence.

Sacrococcygeal teratoma

Sacrococcygeal teratomas are commonly diagnosed in the prenatal period, and complications may occur in utero, or during or after birth.

Potential complications in utero include polyhydramnios and tumor hemorrhage, which can lead to anemia and nonimmune hydrops fetalis. If significant atrioventricular (A-V) shunting occurs within the tumor, 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 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.

Postpartum, morbidity associated with sacrococcygeal teratomas is attributable to associated congenital anomalies, mass effects of the tumor, recurrence, and intraoperative and postoperative complications. Approximately 10% 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 including 57 cases of benign teratomas over a 40-year period from a single institution, there were 5 recurrences. 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. Three patients died in this series. One died with group B sepsis prior to surgery, one died of disseminated intravascular coagulation and sepsis 2 days after surgery, and one died of massive intraabdominal hemorrhage thought to be unrelated to the surgery. No significant change in morbidity or mortality could be identified over the 40-year period of the study.

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 3.2-16% of cases. Several series demonstrate that increasing tumor size correlates with increased risk of torsion.

Rupture of a cystic teratoma may be spontaneous or associated with torsion and occurs in approximately 1-4% of cases. 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 usually is favorable, but the rupture often results in the formation of dense adhesive disease.

Infection is uncommon and occurs in only 1% of cases. Coliform bacteria are the organisms most commonly implicated.

Autoimmune hemolytic anemia has been associated with mature cystic teratomas. In several series, 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 the 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, the mature cystic teratoma of the ovary always is benign, but in approximately 2% of cases, it may undergo malignant transformation into one of its elements. The prognosis for patients with malignant degeneration is dismal, with 5-year survival rates reported in the range of 15-31%. The prognosis appears to be somewhat better if the malignant element is squamous rather than an adenocarcinoma.

Testicular teratoma

Testicular teratomas occur in children and adults. In children, they behave as a benign tumor, whereas in adults and adolescents they invariably are malignant neoplasms.

Childhood testicular teratomas are uniformly benign, with no documented cases of retroperitoneal or lung metastasis in differentiated lesions. Most morbidity is a result of surgical or postoperative complications, such as hemorrhage or infection. The mortality rate is less than 1 per million.

Pure teratomas of the testis are rare. However, during and after puberty, even mature teratomas (composed of entirely mature histologic elements) can metastasize to the retroperitoneal lymph nodes or systemically regardless of their histologic appearance. Morbidity is associated with tumor growth, which may invade or obstruct local structures and become unresectable. Malignant transformation is significantly higher in testicular teratomas compared to their ovarian counterparts, and recurrence risk is around 20% in both mature and immature testicular teratomas.

Mediastinal teratoma

Mature teratomas of the mediastinum are benign lesions. They do not have the metastatic 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 often are intimately involved with the tumor.

Sex: 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.

Age: The presenting location of teratomas correlates with age.



Physical: See History

Causes: The existence of teratomas has been recognized for centuries, during which time their origin was a matter of speculation and debate. Common early beliefs blamed ingestion of teeth and hair, as well as curses from witches, nightmares, or even adultery with the devil. The parthenogenic theory, which suggests an origin from the primordial germ cells, is now the most widely accepted. This theory is bolstered by the anatomic distribution of the tumors along lines of migration of the primordial germ cells from the yolk sac to the primitive gonads. Additional support came from Linder and associates while studying ovarian mature cystic teratomas. They used sophisticated cytogenetic techniques to demonstrate that these tumors are of germ cell origin and arise from a single germ cell after the first meiotic division.


Adnexal Tumors
[Benign Lesions of the Ovaries]

Borderline Ovarian Cancer
Ectopic Pregnancy
Endometrial Carcinoma
Extragonadal Germ Cell Tumors
Fallopian Tube and Broad Ligament Disorders
Germ Cell Tumors
Granulosa-theca Cell Tumors
Lymphoma, Mediastinal
Lymphomas, Endocrine, Mesenchymal, and Other Rare Tumors of the Mediastinum
Malignant Lesions of the Fallopian Tube and Broad Ligament
Malignant Lesions of the Ovaries
Mediastinal Cysts
Neurogenic Tumors of the Mediastinum
Ovarian Cancer
Ovarian Cysts
Ovarian Dysgerminomas
Peritoneal Cancer
Pilonidal Disease
Rectal Prolapse
Spinal Malformation
Testicular Choriocarcinoma
Testicular Seminoma
Testicular Torsion
Testicular Trauma
Testicular Tumors: Nonseminomatous
Thymic Tumors

Other Problems to be Considered:

Sacrococcygeal teratomas should be differentiated from neural tube defects, specifically meningoceles or meningomyeloceles. Also included in the differential are epidermoid cysts, anal duct or pilonidal cysts, rectal abscesses, lymphangiomas, imperforate anus, and rectal prolapse.

Ovarian cystic teratomas should be differentiated from other benign or malignant ovarian neoplasms, endometriomas, tuboovarian abscesses, pedunculated uterine fibroids, hydrosalpinxes, ectopic pregnancies, pelvic kidneys, and peritoneal cysts.

Testicular teratomas should be differentiated from juvenile granulosa cell tumors, cystic dysplasia of the rete testes, testicular cystic lymphangioma, and simple testicular cysts.

Mediastinal teratomas should be differentiated from other mediastinal masses, including neurogenic tumors (20%), thymomas (19%), primary cysts (18%), lymphomas (13%), and germ cell tumors (10%). Other less common mediastinal masses include primary carcinomas, mesenchymal tumors, endocrine tumors, giant lymph node hyperplasia, chondromas, and extramedullary hematopoiesis.


Lab Studies:

Imaging Studies:


Histologic Findings: In cystic teratomas, the outside of the tumor wall usually is lined with native tissue. The cavity of the cyst often is lined with keratinized squamous epithelium and usually contains abundant sebaceous and sweat glands. Hair and other dermal appendages usually are present. Occasionally, the cyst wall is lined with bronchial or gastrointestinal epithelium. Foreign body giant cell reactions may be seen in various parts of the tumor and may, in the case of intraperitoneal teratomas, lead to the formation of extensive adhesions if the tumor contents are spilled. Ectodermal tissue encountered may include brain, glia, neural tissue, retina, choroids, and ganglia. Mesodermal tissue is represented by bone, cartilage, smooth muscle, and fibrous tissue.

One report described an asymptomatic 11-cm ovarian dermoid cyst that contained a mandible with 7 teeth. Representative endodermal tissues include gastrointestinal, bronchial, thyroid, and salivary gland tissue. Representative proportions of various germ cell tissue in a careful histopathologic study of 100 cases of ovarian teratomas found ectodermal structures in 100%, mesodermal structures in 93%, and endodermal structures in 71% of cases.

Staging: Sacrococcygeal teratomas are the only teratomas with a widely accepted staging or classification system. In a study of 405 patients treated by members of the Surgical Section of the American Academy of Pediatrics, Altman and associates report the following system.


Surgical Care: The treatment of mature teratomas is largely surgical.


Special Concerns:


Caption: Picture 1. Ovarian mature cystic teratoma exhibiting multiple tissue types
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Caption: Picture 2. A 12-cm ovarian mature cystic teratoma prior to excision
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Caption: Picture 3. Ovarian mature cystic teratoma with hair, sebaceous material, and thyroid tissue
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Caption: Picture 4. Large teratomatous epignathus diagnosed by prenatal ultrasound
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Picture Type: Photo