After the 19th century, most reports proposed abnormal fertilization as the most likely origin of these tumors; the concept of a “fetus within a fetus” became quite popular. The occurrence of a teratoma in a prepubertal girl with an “intact hymen” disproves this notion. The lack of human tissue in mature teratomas often supports the idea that these tumors occur in the ovary. It is now believed that 2/3 of mature teratomas arise from a single germ cell that has failed to divide at second maturity or from an intranuclear replication of a mature egg. The remaining mature teratomas and most immature teratomas arise from abnormal mitotic divisions of germ cells prior to maturation, or due to failure of the first maturation division. Some immature teratomas can also occur from the fusion of two eggs. Most teratomas have a karyotype of 46, XX: a few have an abnormal karyotype. Abnormal karyotypes are most common in higher grade immature teratomas. I. What is a teratoma? The term “teratoma” is used to describe a teratoma. The term “teratoma” refers to an unattractive, oddly shaped body, while the term “fetus” refers to a fetus that contains components similar to those of a fetus. The source of the tumor is indeed the germ cells in the female ovaries or male testicles, but it should be clarified that teratoma is not a tumor that evolves after a woman has conceived a strange fetus and has nothing to do with marriage or sexual life. We know that the primordial germ cells mature into an egg, and after fertilization by union with sperm, they differentiate towards the embryo. After the fertilized egg is divided into two, two and four, and four and eight …… gathered into a mass to form an embryo, it initially differentiates into three major types of tissues: ectoderm, mesoderm and endoderm, and then each differentiates into the corresponding organ and eventually matures into a fetus. In the absence of fertilization, the body’s primordial germ cells may also undergo abnormal differentiation, also into three types of tissues: ectoderm, mesoderm and endoderm, but eventually fail to differentiate into complete organs, thus forming a tumor, which is a teratoma. The tumor will have ectodermal components such as hair, grease, skin, teeth, bone fragments, etc. It may also have mesodermal or endodermal tissues such as muscle, gastrointestinal, and thyroid tissues. Who can get teratoma? In terms of gender, teratoma is mostly found in women. Teratoma can also occur in men, but it is very rare …… In terms of location, ovaries are the most common site of occurrence. However, teratomas can also occur in midline areas of the body, such as the mediastinum, anterior spine, and pelvis, but of course they are very rare. In terms of age, teratoma can occur in both young girls and older women, but most of them occur in women aged 20-30. Is there any difference between good and bad teratoma? Of course! About 97% of teratomas are benign teratomas. Most benign teratomas that occur in the ovaries are cystic in nature, also known as dermatomal cysts. The shape of the tumor is round or oval with a smooth envelope on the outside. The cystic cavity is most often filled with hair masses and oil. The grease is runny at human body temperature (or thickened to a cheese-like substance), and the tumor coagulates to a semi-solid at room temperature shortly after cutting down. The tubercles also often contain teeth and bone fragments, which can number in the dozens. The tumor can also have solid portions within it that become cephalic segments. The tissue within the tumor is well differentiated, so the tumor is benign. If the differentiation is immature, it is malignant. 4. What are the oddities of teratoma? In some teratomas, the differentiated mature hair-covered head segments resemble the fetal scalp, which looks really scalp-tingling. Some of the bone fragments differentiate into irregular bone fragments, while others differentiate into something almost identical to a child’s teeth. The bone fragment-like material has poor light transmission. If a high-density image is found on ultrasonography or X-ray, it is a good thing, indicating that the tumor is mostly benign. However, only about half of the benign teratomas will have this reassuring test result. V. What is teratoma torsion? Because teratomas are mostly of medium size (fist size, 5-10 cm), and the contents are of varying density, the center of gravity is usually to one side, heavy, and will follow the movement when the body position changes such as exercise or sex, sometimes the movement is too much and twisting will occur. It can be twisted half a turn or several turns. The consequences of cyst torsion are serious, equivalent to ovarian suicide! Because the blood supply to the ovaries and the teratoma is blocked after torsion, if you don’t believe it, twist a cucumber on the melon shelf several times from the tip to see if it is still alive. Severe abdominal pain and nausea can occur after the cyst is twisted. If not treated in time, the ovary can become necrotic and the tumor may rupture with increased tension, and the contents of the tumor (mainly grease) can break into the abdominal cavity and cause chemical peritonitis, which, in addition to being very painful, may also lead to future abdominal adhesions. VI. When do I need surgery? Once the diagnosis of mature cystic teratoma of the ovary is established, surgery is most likely required, it is just a matter of time. As for the specific size of the diameter that warrants surgery, it is still being studied in depth. Generally speaking, if the tumor is not more than 5 cm in diameter, surgery can be withheld for the time being and reviewed regularly. However, if the patient has a need for fertility in the near future, the threshold should be lowered a bit, and a diameter of more than 4 cm is worth surgery.