Teratomas are rare congenital tumors derived from embryonic germ cells.
Beyond the newborn period, symptoms of teratomas depend on its location and organ of origin. Symptoms are caused by extension and interference with surrounding tissue and organs. They may extend into the pelvis and abdominal cavity causing compression and obstruction of internal organs, and interruption of blood flow in the region . Symptoms may include :
Teratomas most often have a midline presentation. Sacrococcygeal teratomas account for approximately 40% of all teratomas . Other common locations include the gonads, anterior mediastinum, and retroperioneum. Even less frequently they appear in the brain, heart, pharynx and pleura .
Diagnosis of teratomas is made primarily by the presence of a mass or tumor containing bone or other tissue fragments through imaging studies and elevated serum tumor markers.
The presence of calcification or bony structures within any mass is diagnostic of teratomas, but are only present in a minority of cases .
Elevated serum levels of (AFP) and b-human chorionic gonadotropin (b-HCG) occur in patients with malignant germ cell tumors .
In immature teratomas, AFP serum levels are elevated in 30–60% of patients, but not all. It is, therefore, not a reliable diagnostic tool. AFP serum levels may also be elevated in patients with mature teratomas but are weaker .
Levels of a-fetoprotein AFP may return to and remain normal even when the tumor has recurred .
Biopsy/histologic examination of resected tumor
Teratomas, regardless of site, have a similar gross appearance and are well circumscribed . Cross sections, shows diverse tissue types. Two or more embryonic germ layers are present in 90% of cases . Mature teratomas are more frequently fluid filled, entirely or partially .
The treatment of patients with teratomas should be based on the histology of the tumor. Standard treatment for primary teratoma is complete surgical resection. There are, however, currently no standards for adjuvant therapy  . Teratomas, especially those with malignant transformation, are usually resistant to chemotherapy .
The treatment of choice for all teratomas is complete surgical resection  . However, removal of all germ cell material is difficult and results in the high rate of recurrence. The most powerful predictor of patient outcome is the completeness of resection  .
This procedure is often used following surgical resection for malignant teratomas or teratomas with the potential of becoming malignant. It is used either alone or in conjunction with chemotherapy.
For malignant teratomas surgery is usually followed by chemotherapy. Recent studies report that chemotherapy in conjunction with radiotherapy may increase the duration and rate of survival in patients with immature teratoma  . Cisplatin/carboplatin-based drugs have proven to be the most effective chemotherapy medications for these tumors . Cisplatinum therapy results in long-term remissions in approximately 80% of patients with teratomas  . Teratomas that are not accessible surgically, are complex, or likely to be malignant may be treated with chemotherapy first.
Although often described as benign, teratomas do have the potential to become malignant and the recurrence rate even in mature teratomas is as high as 40% . Follow-up examinations should be performed frequently by measuring the tumor markers, AFP and b-HCG  repeated imaging to detect recurrence . Teratomas may result in significant morbidity, either due to the malignancy or as a result of the surgery, radiation, or chemotherapy . Careful long-term follow-up is necessary for early identification and treatment of complications . With microscopically complete tumor resection, adjuvant chemotherapy or radiotherapy is not required  . The difficulty lies in determining absolutely that there are no residual tumor cells remaining.
Prognosis is good for primary, benign teratomas with complete resection approximately 92-100%   . Patients with mature teratoma with germinoma have a 5-year survival rate of 68%  . The poor prognosis in teratomas, can be attributed to the high rate of recurrence. The addition of chemotherapy has improved prognosis .
Histology and primary site have a significant impact on survival rates for patients with malignant germ cell tumors . Treatment recommendations should be based on the histologic type. In patients with mature teratoma complete surgical resection produce excellent results. Resection and radiotherapy have been used as well .
Several recent studies show that chemotherapy may improve the overall duration and rate of survival when used in conjunction with radiotherapy as . Cisplatin/carboplatin-based chemotherapy is the drug of choice.
Complete clinical remission is defined as normal levels found residual tumors in up to 40% of patients even when tumor markers return to normal. Most relapses occur within two to five years of diagnosis . More than 90% of relapses occur at the site of the original tumor.
Fetal teratomas result in perinatal mortality of 25% to 37% . In fetuses with fast growing, solid and vascularized teratomas the mortality rate is even higher. These lesions cause cardiac failure due the increased vascular needs of the tumor.
Several variables have been identified that pin point patients at high-risk for disease recurrence. These include primary tumor of the mediastinum, increased tumor burden, and immature teratoma histology .
The word teratoma comes from the Greek "teratos" meaning monster and denotes the tortuous or malformed appearance of the tumor .
Teratomas are divided into three subgroups according to the extent of differentiation in the tumor cells. The three types are mature teratomas, immature teratomas, and mixed or teratoma with malignant transformation .
Teratomas are derived from embryonic germ cells and are present at birth , though often not found until adulthood. The peak incidence is 20 to 30 years of age . Retroperitoneal teratomas tend to occur in early childhood and are rarely seen in adults .
The overall incidence of teratoma is estimated to be 0.9 per 100,000 in children . Approximately 2.9% of all malignant tumors in children are malignant germ-cell tumors .
The incidence of teratoma is higher in females, but the risk of malignant teratoma is higher in males .
The distribution of teratomas is reported as 26% in the sacrococcygeal region, 24% in ovaries, 18% in testes and 18% in the brain  .
Mature, benign teratomas are the most frequent form, accounting for approximately 54.5 %. Immature malignant teratomas account for about 45.5 %.
Teratomas are not well understood. The pathophysiology of teratomas depends on several factors, patient age at diagnosis, sex, tumor site, and cell histology, which result in different cytogenetic and molecular abnormalities . Teratomas originate from two or more germ cell layers (endoderm, ectoderm, or mesoderm) and may be histologically diverse . Teratomas are thought to arise from primordial germ cells. These cells undergo physiologic alterations that change their gametogenesis in the developing gonad   . Teratomas are thought to be present at birth (congenital), but small ones are often not discovered until much later in life.
There are three histologic variations of teratoma: mature, benign teratomas, immature, malignant teratomas, and mature teratoma with germinoma .
Mature teratomas are benign. They do not infiltrate adjacent organs and can be resected completely. These tumors are often cystic lined with mature squamous epithelium . Their walls may contain various tissues, cartilage, bone, nerve tissues or organ tissue  . Mature teratomas with germinoma can grow extensively, recur, and, in some cases, transform into malignancies .
Teratomas are also classified according to the Gonzalez-Crussi  grading system, a cancer staging system. Teratomas are classified as: 0 - mature (benign); 1- immature, probably benign; 2 - immature, possibly malignant (cancerous); or 3 - frankly malignant .
Teratomas are also classified by their content: solid teratomas contain only tissue; cystic teratomas contain only fluid; mixed teratomas containing both solid and cystic components.
Teratomas have their origin in totipotential cells, normally present in the ovary and testes , as a result certain hormones are often elevated when teratomas are present. These can be used as tumor markers and include serum α-fetoprotein (AFP), β-human chorionic gonadotropin (β-hCG), CA-125, and CA15-3 .
There is currently no way to prevent the occurrence of teratomas, as their cause is not understood. The impact, morbidity, and mortality associated with the disorder may be decreased by early identification and treatment of the tumors.
Routine fetal screening programs, fetal ultrasound with Doppler and magnetic resonance imaging, allow for prenatal diagnosis of some forms of teratoma . They may go a long way to avoid intrauterine fetal death and serious fetal and maternal complications .
Teratomas are rare congenital tumors consisting germ cell components of various tissue types. They often contain all three dermal layers: ectoderm, endoderm and mesoderm  , as well as bone, and organs  . Teratomas are present at birth, but are often not discovered until much later  .
Most teratomas are benign, but they can be innately malignant or have the potential to transform to a malignant form . Even benign teratomas grow aggressively and extend into the surrounding tissue causing damage to the nearby organs and tissue obstructing blood flow  .
What are teratomas?
Teratomas are a rare form of tumor which contain embryonic germ cells, cells with the ability to become other tissues. They may contain all three dermal layers, bone, or components of other organs. Teratomas are congenital, present at birth, and are often diagnosed in the fetus or newborn. There are three types of teratoma: mature teratomas which are benign, immature teratomas which are cancerous, and mature teratomas with the ability to transform into the malignant form.
What are the symptoms of teratomas?
The symptoms of teratomas depend on the location, size, and degree they invade surrounding tissue and organs. Symptoms include:
What causes teratomas?
The cause of teratomas is not known. They are thought to be the result the abnormal development of embryonic germ cells.
Who develops teratomas?
Teratomas can occur in anyone. Peak age at diagnosis is 20 – 30 years of age. They are more common in females than males. Incidence is not affected by race or ethnicity.
How are teratomas diagnosed?
There are two ways of diagnosing teratomas:
How are teratomas treated?
All types of teratomas are treated first by complete surgical removal of the tumor. This may be all that is needed for mature, benign teratomas. Mature teratomas with the potential for becoming malignant may benefit from the addition of radiotherapy after surgery. Immature, malignant, teratomas are usually treated with radiotherapy and chemotherapy.
What are the complications of teratomas?
Teratomas recur in approximately 40% of patients.
Complications of teratomas are related to the effects of the treatment: surgical intervention, radiotherapy, and chemotherapy. Other complications may result from the invasion into the surrounding tissue and organs, and obstruction of blood flow caused by the tumor itself.
What can we do to prevent the complications of teratomas?
The recurrence and complications of teratomas can be prevented by early detection and treatment of the tumors and frequent follow-up.