The term teratoma refers to a group of complex tumors. The most common forms are ovarian teratoma in women and testicular teratoma in men. Their management consists mainly of removing the tumor by surgery.

Definition of teratoma

Teratomas are tumors that can be benign or malignant (cancerous). These tumors are said to be germinal because they develop from primordial germinal cells (cells that produce gametes: spermatozoa in men and ova in women).

The two most common forms are:

• ovarian teratoma in women;
• testicular teratoma in men.

However, teratomas can also show up in other areas of the body. We can in particular distinguish:

• sacrococcygeal teratoma (between the lumbar vertebrae and the coccyx);
• cerebral teratoma, which manifests itself mainly in the epiphysis (pineal gland);
• mediastinal teratoma, or teratoma of the mediastinum (region of the chest located between the two lungs).

Classification of teratomas

Teratomas can be very different. Some are benign while others are malignant (cancerous).

Three types of teratomas are defined:

• mature teratomas which are benign tumors made up of well-differentiated tissue;
• immature teratomas which are malignant tumors made up of immature tissue still resembling embryonic tissue;
• monodermal or specialized teratomas which are rare forms which may be benign or malignant.

Cause of teratomas

Teratomas are characterized by the development of abnormal tissue. The origin of this abnormal development has not yet been established.

People affected by teratomas

Teratomas represent 2 to 4% of tumors in children and young adults. They represent 5 to 10% of testicular tumors. In women, mature cystic teratomas represent 20% of ovarian tumors in adults and 50% of ovarian tumors in children. Brain teratoma accounts for 1 to 2% of brain tumors and 11% of childhood tumors. Diagnosed before birth, sacrococcygeal teratoma can affect up to 1 in 35 newborns. 

Diagnosis of teratomas

The diagnosis of teratomas is usually based on medical imaging. However, exceptions exist depending on the location of the teratoma and its development. Blood assays for tumor markers can, for example, be carried out in certain cases.

Some teratomas may go unnoticed while others will cause significant discomfort. Their symptoms depend not only on their form but also on their type. The paragraphs below give a few examples but do not cover all forms of teratomas.

Possible swelling

Some teratomas can manifest as swelling of the affected area. For example, an increase in testicular volume can be observed in testicular teratoma. 

Other associated signs

In addition to the possible swelling in certain locations, a teratoma can induce other symptoms such as:

• abdominal pain in ovarian teratoma;
• respiratory discomfort when the teratoma is localized in the mediastinum;
• urinary disorders or constipation when the teratoma is localized in the region of the coccyx;
• headache, vomiting and visual disturbances when the teratoma is located in the brain.

Risk of complications

The presence of a teratoma may present a risk of complications. In women, ovarian teratoma can lead to several complications such as:

• an adnexal torsion which corresponds to a rotation of the ovary and the fallopian tube;
• infection of the cyst;
• a ruptured cyst.

The management of teratomas is mainly surgical. The operation involves removing the teratoma. In some cases, surgery is supplemented by chemotherapy. This relies on chemicals to destroy diseased cells.

The mechanisms involved in the development of a teratoma are not yet fully understood and this is why there is no specific prevention.