Teratoma is a common type of ovarian germ cell tumor. It is not a tumor that evolves after a woman has a freak pregnancy, but is derived from germ cells and contains three tissue components: human ectoderm, mesoderm and endoderm, so the tumor will have ectodermal tissues such as hair, oil, skin, teeth and bone fragments, and may also have meso- or endodermal tissues such as muscle, gastrointestinal and thyroid tissues. It does look strange, but it really is not a case of having a freak baby. There are several types of teratomas, 97% of which are cystic mature teratomas, also called dermatomal cysts. They can occur in both young girls and older women, but the vast majority are in their 20s and 30s. Cysts are round or oval in appearance, with a smooth envelope outside, and the cystic cavity is most often filled with hair masses and grease, which is fluid at human body temperature and condenses to a semi-solid at room temperature soon after the tumor is cut. The tubercle also often contains teeth and bone fragments, and the teeth can be as many as several dozen. These tissues are well-differentiated, so the tumors are benign. Dermatomal cysts are mostly of medium size, often with a tip, and the contents of the tumor are light and heavy, with the center of gravity to one side, heavy and easily twisted. Severe abdominal pain and nausea can occur when the mass twists. If the tumor breaks and gets a belly full of grease in one go, there are even cases of breaking into the nearby adherent bladder or intestinal cavity. Dermatomal cysts require surgical treatment. About 25% of dermatomal cysts are bilateral, so it is important to examine the other ovary carefully during surgery. Sometimes a small dermatomal cyst may be found on dissection after a normal appearance. Dermatomal cysts do not interfere with ovarian function, so conception is normal. There are also cases where a pregnancy is carried with the tumor and the tumor is not detected until the pregnancy is checked. In this case, surgery is usually done at 14 to 16 weeks of gestation because it is less likely to cause miscarriage at this time. The malignancy rate of dermatomycosis is 1% to 3%, and it occurs mostly in older patients, and the average age of malignancy is 51 years. It is usually malignant to squamous carcinoma. There are certainly such stem cells in the tissues of human ovaries and testes. The biggest difference between it and stem cells from other parts of the body is that it has the characteristic of differentiation to germ cells. Our entire body is derived from germ cells. No matter how sophisticated an organ or how complex a system is, it all comes from germ cells. That is, germ cells have the ability to differentiate into various tissues, cells and organs of the body. For a germ cell to develop into an organism, it must be fertilized by chromosomal pairing of germ cells from both parents and divide continuously. A germ cell that has not undergone chromosome pairing will never grow into a new individual under natural circumstances. Stem cells from the ovaries or testes are transformed into more naive germ cells by some factor. These infantile germ cells still have the potential to develop into various tissues and cells of the body. This infantile germ cell keeps dividing and the tumor formed will have many tissues and cells that may be completely different. The most common are skin and hair. Other components can also be present. For example, fatty tissue, various muscle tissues, brain and bone tissues, etc. The presence of teeth makes it easier to diagnose a teratoma. Correcting several misconceptions about teratoma 1. Teratoma has nothing to do with twin siblings Teratoma is a tumor. A tumor that originates from germ cells. Most teratomas are ovarian teratomas, which are caused by abnormal proliferation of oocytes. As the oocytes are allogenically differentiated and overproliferate, a tumor is formed. The oocyte is not fertilized, so it is not true that “it is the patient’s twin sibling”. No doctor would tell a patient that this teratoma is a result of pregnancy. The tumors associated with pregnancy are staphyloma, malignant staphyloma and chorioepithelial carcinoma. The malignant staphyloma and chorioepithelial carcinoma can also occur in non-pregnancy. 2. Are teratomas inherent? The age of onset of teratoma can be as young as a newborn baby or as old as a woman in her nineties. Ovarian teratoma usually occurs in young women in their twenties and thirties, and will grow with age. Teratoma is not brought from the mother, but is a tumor that can erupt at any time. 3. Teratomas are also found more often in men. The name “teratoma” is easily misunderstood, as the word “fetus” reminds people of pregnancy, which has caused some innocent girls to be wronged. The legend of the so-called teratoma being a sibling has given it a legendary tinge. But the truth is, teratoma is what it is: a tumor! The actual fact is that you can find a lot of people who have been in the business for a long time. 4, the discovery of teratoma recommended surgery to remove. The actual fact is that once a teratoma is discovered, doctors recommend removing it. The first is that the presence of ovarian teratoma may affect the fertility of women; the second is that whether the teratoma is benign can only be determined by pathological tests after removal, and the teratoma has a certain rate of malignancy, not removed is equivalent to carrying a time bomb, which may explode at any time. Thirdly: Ultrasound suggests that the symptoms may be teratoma, but it does not exclude other cases, and pathological examination must be done after surgery to make a final determination. Therefore, even if there is no symptom and it does not affect the daily life, and the vast majority of teratoma is benign, it should be operated. 5.Will the removal of teratoma affect fertility? After surgery for ovarian teratoma, it is possible to get pregnant normally, and there is not much harm to the body. 6.What if it is a malignant tumor? Generally speaking, the lower the incidence of malignancy in teratoma found in the reproductive age. At present, the survival rate of malignant ovarian teratoma can reach 97% after complete resection with comprehensive treatment, while the survival rate of those with intraoperative residual or recurrence can be improved.