Mature teratoma of the ovary

　　Mature teratomas are composed of tissues derived from well-differentiated ectoderm, mesoderm, and endoderm (with the ectoderm component being the most), and cell genetic studies have found that the vast majority of mature teratomas show a normal 46, XX karyotype, and in a few cases, the karyotype of the teratoma can be trisomic or triploid.
　　Cell and molecular genetic studies have shown that although the karyotype of the teratoma tissue is 46, XX, there is a genetic difference from the host's karyotype. Research on nuclear heterogeneity of chromosome centromeres has found that the female host mostly shows a heterozygous karyotype, while the teratoma tissue mostly shows a homozygous karyotype. Some authors have studied the chromosome terminal isoenzyme sites and found that although the heterogeneity of the centromere of the teratoma tissue karyotype is shown as a homozygote, the chromosome terminal isoenzyme sites are shown as heterozygous as the host, thus considering that benign teratomas originate from a single germ cell that fails in the second meiotic division or fuses with the ovum, that is, the so-called asexual reproduction process. Subsequently, some authors found that some mature teratomas have centromere heterogeneity markers completely consistent with the nuclear type of host cells and proposed that the failure of the first meiotic division is also one of the mechanisms of teratoma occurrence.
　　In summary, there are five possible mechanisms for the occurrence of mature ovarian teratomas:
　　1. Failure of the first meiotic division of the oocyte or fusion of the first polar body with the ovum (Type I) is characterized by the centromere markers of the tumor tissue and host cells being all heterozygous; while the chromosome terminal isoenzyme sites can be either heterozygous or heterozygous, depending on whether there is crossover and the frequency of crossover during meiosis. If no crossover occurs, it is shown as terminal marker heterozygosity. If there is one crossover, 50% is shown as heterozygosity, and if there are two crossovers, 75% is shown as heterozygosity.
　　2. Failure of the second meiotic division or fusion of the second polar body with the ovum (Type II) is characterized by the centromere markers of the teratoma chromosomes being all heterozygous, while the chromosome terminal markers can be either heterozygous or heterozygous depending on whether or not there is crossover during meiosis.
　　3. The mature oocyte's genomic nucleus undergoes self-replication (Type III), and the centromere markers and chromosome terminal markers of this type of teratoma are all heterozygous.
　　4. The first and second meiotic divisions of the primordial germ cells fail (Type IV), and this type does not undergo meiosis. After mitotic division, the teratoma formed has centromeres and terminal markers consistent with the host, showing heterozygosity.
　　5, Caused by the fusion of two eggs (V-type) The chromosomes of this type of teratoma can be either heterozygous or homozygous for centromere and terminal markers.
　　The karyotype analysis of mature teratomas is 90% above 46, XX, with a small number showing numerical or structural abnormalities, of which trisomy is most common, with an incidence of chromosomal abnormalities in mature teratomas of about 7%; in contrast, the incidence of chromosomal abnormalities in immature teratomas is over 60%, with trisomy being the most common, and chromosomal structural abnormalities can also be encountered. The chromosomes commonly found with structural abnormalities are chromosomes 3, 5, 7, 8, and 9. Studies have shown that immature teratomas have the biological characteristics of transforming into mature teratomas, but after immature teratomas revert to mature teratomas, whether their abnormal karyotypes also become normal diploid karyotypes at the same time? Studies have shown that after chemotherapy induction, the abnormal karyotypes of immature teratomas do not reverse.
 

　　Mature ovarian teratomas belong to benign tumors and generally have a good prognosis with timely treatment. If left untreated, although less common, it may still lead to the following complications.
　　1, Tumor rupture:About 3% of ovarian tumors may rupture, including ovarian tumor pedicle torsion, which can be traumatic or spontaneous. Traumatic rupture often occurs due to abdominal blows, childbirth, sexual intercourse, gynecological examination, and puncture, while spontaneous rupture often occurs due to rapid growth of the tumor, with most cases being infiltrative growth of the tumor piercing the capsule wall. The severity of symptoms depends on the size of the rupture, the nature and quantity of the fluid in the peritoneal cavity, and the type of cystadenoma. When small cysts or simple serous cystadenomas rupture, patients may only experience mild abdominal pain. When large cysts or mature teratomas rupture, they often cause severe abdominal pain, nausea and vomiting, and sometimes lead to internal hemorrhage, peritonitis, and shock.
　　2, Infection:It is less common and often caused by torsion or rupture of the tumor, or can come from adjacent organ infection foci such as appendiceal abscess spread. Clinical manifestations include fever, abdominal pain, mass, abdominal tenderness, muscle tension, and elevated white blood cell count. Treatment should first use antibiotics, followed by surgical resection of the tumor. If infection cannot be controlled within a short period, immediate surgery is recommended.
　　3, Pedicle torsion:It is relatively common and is one of the gynecological acute abdomen diseases. About 10% of ovarian tumors are accompanied by torsion of the pedicle. It is more common in cystic tumors with long pedicles, medium size, high mobility, and a center of gravity偏向一侧. It often occurs during sudden changes in body position, in the early stages of pregnancy, or after childbirth. The pedicle of the ovarian tumor consists of the infundibulopelvic ligament, the ovarian ligament, and the fallopian tube. After acute torsion, venous return is obstructed, causing severe congestion within the tumor or vessel rupture, leading to rapid increase in tumor size, intratumoral hemorrhage, and finally, obstruction of arterial blood flow, resulting in necrosis of the tumor turning purple-black, making it prone to rupture and secondary infection.
　　4, Malignant transformation:Malignant transformation of ovarian benign tumors often occurs in older individuals, especially postmenopausal women. The tumor may rapidly increase in size within a short period, causing symptoms such as abdominal distension, loss of appetite, and significant increase in tumor volume. The tumor becomes fixed, and there is often ascites. Those suspected of having malignant transformation should be treated promptly.

　　Mature teratoma of the ovary can occur at any age, and the vast majority occur in women of childbearing age around 30 years old. Patients usually have the following clinical manifestations:
　　1. The tumor is mostly unilateral, with similar incidence rates on the left and right sides, and is benign.
　　2. Without torsion or infection and other complications, there are usually no special symptoms.
　　3. If the tumor volume is large, it can cause a feeling of abdominal distension, mild abdominal pain, and compression symptoms.
　　4. Combined pregnancy, which is the most common type of pregnancy complicated with ovarian tumor.
　　5. In a very few cases, the ovarian stroma where the tumor occurs has flavinization changes, resulting in a sign with a lot of hair.

　　The etiology of mature teratoma of the ovary is unknown at present, and there is no effective preventive method. The current focus of prevention is on regular gynecological examinations and pelvic examinations for high-risk populations, to achieve early diagnosis and early treatment.

　　Laboratory tests have little diagnostic significance for mature teratoma of the ovary, and diagnosis is mainly based on physical examination, pathology, and imaging examination results.

　　I. Gross examination

　　1. It is mostly unilateral, with similar incidence rates on the left and right sides, but most are 5-15 cm in size.

　　2. The mass is circular, elliptical, or lobulated, with a smooth surface and intact capsule.

　　3. The section is mostly a large cyst containing hair and sebaceous-like substances.

　　4. The inner wall of the cyst often shows solid or cystic-papillary nodules, with hair and teeth on the surface of the nodules. The section shows bone, cartilage, and fatty tissue.

　　II. Microscopic examination

　　It is often accompanied by giant cell reaction to foreign bodies. The outer wall of the cyst is ovarian stroma, and the inner wall is lined with skin, hair, and skin appendages. The head nodules are often visible with multiple tissues of three germ layers.

　　III. Ultrasound diagnosis

　　1. Cystic dough sign

　　A strongly reflective light mass appears inside the cyst, mostly circular, which can adhere to the inner wall. There is no echo behind the light mass.

　　2. Cyst-like type

　　Mostly circular or elliptical, the cyst wall is thick, mostly unilocular, with dense and strong reflective light points inside.

　　Occasionally, a thin liquid area can be seen at the inner wall.

　　3. Cystic mass sign

　　A circular light mass can be seen inside the cyst, with a crescent-shaped strong echo above, followed by attenuation and a significant acoustic shadow at the back.

　　4. Cystic lipid-liquid stratification sign

　　(1) Upper lipid substance: strong reflection, dense light point echo.

　　(2) Lower layer: clear liquid, or a small amount of light points floating in the liquid.

　　(3) Between the two layers: the lipid-liquid stratification plane.

　　5. Complex type

　　The internal structure of the cyst is complex and can have two or more types mentioned above.

　　IV. X-ray diagnosis

　　There are greasy substances, teeth, and bone fragments inside the tumor: there are bone and tooth shadows, calcified shadows in the contents of the cyst. There are sebaceous substances and hair inside the tumor: transmittance is weakened or there are clear circular or oval shadows with clear contours.

　　V. Other

　　Tumor marker tests, laparoscopic examination.

　　The dietary注意事项 for patients with mature teratoma of the ovary after surgery include the following aspects.

　　1. After anesthesia, patients are required to fast for 6 hours before they can consume liquid diet without sugar and milk. After the anus recovers and starts to pass gas, they can have semi-liquid food, and after defecation, they can eat regular food.

　　2. Consume high-protein, high-vitamin foods, and keep the bowels regular.

　　3. Eat more nutritious foods after surgery: sesame, almond, wheat, barley, loofah, etc.

　　4. Eat more foods with antitumor effects: turtle, horseshoe crab, sea horse, dragon pearl tea, hawthorn, etc.

　　5. Infection: Eat eel, carp, toon, water snake, celery, sesame, rapeseed, buckwheat, mung bean, clam, red bean, etc.

　　6. Bleeding: Eat goat blood,螺蛳, cuttlefish, herring, spinach, sesame, rapeseed, buckwheat, mung bean, clam, red bean, etc.

　　7. Abdominal pain and distension: Eat pork kidneys, myrica, hawthorn, walnuts, chestnuts, etc.

　　8. Postoperative Qi and Blood Tonification: Eat foods such as longan, jujube, and mother chicken soup that are warm and nourishing, and do not eat cold foods. However, those with ulcerative and bleeding symptoms should not eat warm and hot foods.

　　9. Abstain from eating allergenic foods: roosters, geese, etc.

　　10. Abstain from eating fried, moldy, greasy, pickled, spicy and刺激性食物.

　　11. Abstain from smoking and alcohol.

　　12. Patients with severe itching symptoms should not eat seafood and刺激性、致敏性食物. Eat more amaranth, cabbage, rapeseed, taro, kelp, nori, etc.

　　Although ovarian mature teratoma is a benign tumor, it can cause complications such as torsion and infection, and there is a possibility of malignancy in a few cases, so surgical resection should be adopted in treatment. The tumor excision method should be adopted to preserve the normal tissue of the affected ovary. When removing the tumor, attention should be paid not to break the tumor and contaminate the peritoneal cavity with the contents of the tumor. A shallow incision can be made below the thinnest part of the ovarian capsule during surgery, as the tumor is located below the thin capsule. At this location, it is relatively easy to find the boundary layer between the tumor and the ovarian capsule. If the layer under the capsule is entered correctly, it is generally relatively easy to continue stripping the tumor, and it can be peeled off smoothly. After the tumor is removed, there is often a lot of normal ovarian tissue left, which can be overlapped and sutured to look like a normal ovary. Using this method to remove the tumor, there is rarely recurrence after surgery.

　　With the increasing application of laparoscopic surgery in gynecological surgery, many studies have shown that laparoscopic surgery can be used as an acceptable alternative surgical method.