A teratoma is a rare type of germ cell tumor that may contain immature or fully formed tissue, including teeth, hair, bone and muscle. Teratomas may be cancerous or noncancerous, and they can affect people of all ages. Treatment involves surgical removal. Cancerous teratomas may require chemotherapy, radiation therapy or other cancer treatments.
A teratoma is a type of germ cell tumor (a tumor that starts in your reproductive cells). Teratomas can contain many different types of tissue, including bone, muscle, teeth and hair. They may be benign (noncancerous) or malignant (cancerous).
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Teratomas most commonly form in the ovaries, testes or tailbone (coccyx) — but they can occur anywhere in the body.
Teratomas can affect people of all ages. Some teratomas form during development in the uterus.
Teratomas are considered rare overall. The frequency at which they occur varies depending on where the tumor is found:
There is another, very rare type of teratoma called fetus in fetu (fetus within a fetus). This type of teratoma is made up of living tissue and it often takes on the appearance of a malformed fetus. However, because there is no placenta or amniotic sac, the fetus has no chance of development. Fetus in fetu teratomas only occur in twins who both share the same placenta and have their own sac of amniotic fluid.
There are two primary theories regarding fetus in fetu teratomas:
Teratomas are divided into two main categories: mature and immature.
People with teratomas may not show any symptoms at first. Once symptoms develop, they can vary significantly depending on where the tumor is located. General teratoma symptoms may include:
Certain types of teratomas often exhibit specific symptoms:
Sacrococcygeal teratomas can form inside or outside your body in the tailbone area. Possible symptoms include:
A main symptom of ovarian teratoma is intense abdominal or pelvic pain. This occurs when the growing mass places excess pressure on the ovary.
In some instances, ovarian teratomas may be accompanied by NMDA encephalitis — a rare condition that can lead to severe headaches, confusion and psychosis.
The primary symptom of testicular teratoma is a lump or swelling in the testicle. In some cases, people with testicular teratoma may not show any symptoms.
Teratomas form in germ cells, which are undifferentiated — meaning they can turn into any type of cell. A teratoma develops when there are disruptions during your cells’ differentiation process.
If your healthcare provider suspects that you have a teratoma, they will perform a physical examination and ask you questions about your symptoms and medical history. They may also order tests, including:
With the development of imaging technology, healthcare providers can sometimes diagnose a teratoma in the fetal stage of development.
First, your healthcare provider will determine if the teratoma is cancerous or noncancerous. Nearly all teratomas should be removed when discovered. Even if they aren’t cancerous, they can still grow rapidly or rupture, leading to other problems. If your teratoma is cancerous, your healthcare provider may recommend chemotherapy, radiation therapy or a combination of the two in addition to surgical removal.
If a teratoma is detected during the fetal stage, your healthcare provider will monitor your pregnancy closely. Small teratomas usually aren’t threatening, and a normal vaginal delivery can be planned. Large teratomas may require early delivery via C-section. Rarely, fetal surgery is necessary to remove the teratoma before it leads to serious complications.
Before planning your treatment, your healthcare provider will take your unique situation into account. Treatment will depend on several factors, including your age, medical history, overall health and personal preferences.
Yes. Most teratomas — even cancerous ones — have excellent survival rates with early diagnosis and treatment.
Anytime you notice a new lump or bump on your skin, you should schedule a visit with your healthcare provider. They can run the appropriate tests and determine a diagnosis. If you’ve already been diagnosed with a teratoma, call your provider any time you develop pain or other new symptoms.
A note from Cleveland Clinic
Teratomas are rare — and in most cases, they’re noncancerous. However, even cancerous teratomas can be treated successfully with prompt diagnosis and treatment. If you’ve been diagnosed with a teratoma, ask your healthcare provider for resources so you can make an informed decision about your health.
Last reviewed by a Cleveland Clinic medical professional on 11/16/2021.
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