Uterine fibroids, also known as uterine smooth muscle tumors, are formed mainly by the proliferation of smooth muscle cells with a small amount of connective tissue in between. Uterine fibroids are the most common benign tumor in female genitalia. It is most common in women aged 30 to 50 years old, with the highest incidence in women aged 40 to 50 years old, accounting for 51.2 to 60%. It is estimated that about 20 to 25% of women aged 30 to 50 years old suffer from uterine fibroids.
Classification
According to the growth site, it is divided into uterine body and cervical fibroids; according to the relationship between fibroids and myometrium, it is divided into the following three types: (1) intermyometrial fibroids: the most common, accounting for 60-70% of fibroids. The fibroids are located in the myometrium and are surrounded by the myometrium. Larger fibroids may enlarge the uterus with uneven texture, and the uterine surface may bulge or protrude into the uterine cavity. (2) Subplasma leiomyoma: It accounts for 20-30% of the cases. The leiomyoma grows towards the plasma surface and protrudes from the uterus, and the surface is covered by the plasma surface only; it may also form a tip, and when the tip is twisted and broken, the leiomyoma falls off into the abdominal cavity to form a free leiomyoma or adheres to the greater omentum or intestinal mesentery to become a parasitic leiomyoma; when the leiomyoma is located in the uterine body and grows to the lateral side between the anterior and posterior lobes of the broad ligament, it forms a broad ligament leiomyoma. (3) Submucosal leiomyoma: 10-15% of the cases. The fibroids grow towards the mucosal surface of uterus and protrude into the uterine cavity, with the surface covered by mucosal surface only, mostly single. Submucosal leiomyoma with a tip can be formed, which is like a foreign body in the uterine cavity, causing uterine contraction that can cause the leiomyoma to drain into the vagina through the cervix and become a submucosal leiomyoma hanging in the vagina.
In this case, the clinical examination and ultrasound examination showed that it was a typical interstitial myoma.
Secondary degeneration
Due to the rapid growth of the myoma, different degeneration can occur when the blood supply is poor. The larger the myoma, the more severe the ischemia, the more secondary degeneration will occur.
1.Benign degeneration
(1) Hyaline degeneration (glassy degeneration) is caused by the rapid growth of leiomyosarcoma, resulting in insufficient relative blood supply, which makes part of the tissue edematous and soft, and the swirling structure disappears and is replaced by uniform hyaline-like material, which is easily confused with sarcoma degeneration during macroscopic examination.
(2) Cystic degeneration is caused by the further development of hyaline degeneration. On the basis of hyaline degeneration, the blood supply is insufficient, which causes the tissue in the degeneration area to liquefy and form a cystic cavity containing jelly-like or transparent fluid.
(3) Necrosis develops due to twisting of the tumor tip or severe infection. The central part of the leiomyosarcoma is far from the blood supply and is most susceptible to necrosis. The tissue is grayish yellow, soft and brittle, and may also form small cavities.
(4) Infection is mostly seen in submucosal leiomyoma protruding into the vagina, where blood supply is obstructed and necrosis occurs, followed by infection; there are also a few patients with infected foci in the pelvis, mostly involving the uterine leiomyoma.
(5) Fatty degeneration often occurs in the late stage of hyaline degeneration or after necrosis, or it may be caused by the formation of adipose tissue due to interstitial growth of fibroids. It is soft and easily diagnosed as a sarcoma. Light microscopy reveals vacuoles within the myocytes and positive fat staining.
(6) Red-like change is a special type of myoma necrosis, mostly seen in a single large interstitial myoma, often occurs in pregnancy or puerperium, may be related to local tissue ischemia, infarction, stasis, thrombus obstruction, resulting in local tissue hemorrhage, hemolysis, so that the blood infiltrates into the tumor, the sarcoma is red, like raw beef-like, completely lost the original swirling structure.
2.Malignant transformation
About 0.5% to 1% of uterine fibroids become malignant to sarcoma, mostly seen in older, larger and fast-growing fibroids, especially in patients with rapid growth of fibroids after menopause or postmenopausal fibroids, the mechanism is unknown. The tissue in the sarcoma lesion area is grayish-yellow and soft like raw fish.
Diagnosis
The patient had typical clinical manifestations of uterine fibroids: interstitial fibroids increase the endometrial area of the uterine cavity, and the contraction of the uterus and possible hyperplasia of the endometrium may cause shortening of the menstrual cycle, prolongation of the menstrual period, and changes in the menstrual flow; the increase in the area of the uterine cavity may also increase the secretion of endometrial glands and pelvic congestion, resulting in increased leucorrhea; anterior uterine wall fibroids may compress the bladder, causing urinary frequency and difficulty in urination. The excessive menstrual flow can cause blood loss anemia, and interstitial myomas usually cause mild to moderate anemia. Interstitial fibroids can be seen on gynecologic examination with an enlarged uterus and a raised surface. Other clinical manifestations of uterine fibroids include abdominal masses and abdominal pain, which are not obvious in this case.
The most effective and widely used adjuvant examination for uterine fibroids is ultrasonography. The ultrasound image shows that the endometrium is echogenically displaced and distorted, and the fibroid is round and hypoechoic, with a circular hypoechoic line around the fibroid. Other auxiliary examinations such as hysteroscopy are mainly used to observe the size and location of submucosal fibroids; laparoscopy is used to observe the size and location of interstitial fibroids and subplasma fibroids. In case of small fibroids, surgical treatment is feasible at the same time.
The diagnosis of uterine fibroids is not difficult. In this case, the diagnosis can be made clearly through clinical manifestations, physical examination and auxiliary examinations.
Differential diagnosis
(1) Pregnant uterus: Pregnant uterus is enlarged and softened, which can be easily identified by history of menopause, urine and blood HCG measurement and ultrasonography.
(2) Ovarian tumor: It is mainly differentiated from subplasmic myoma with tissues and myoma cystic change. Ovarian tumors usually do not have menstrual changes and there is no direct connection between the tumor and the uterus on gynecological examination. It can be differentiated by ultrasound and laparoscopy.
(3) Adenomyosis of the uterus: It is difficult to differentiate from leiomyosarcoma. Adenomyoma is usually associated with secondary progressive dysmenorrhea and infertility with uniform enlargement of the uterus. There is no myoma image on ultrasonography.
(4) Uterine sarcoma: similar clinical features to fibroids, more difficult to differentiate. Cytologic examination and diagnostic curettage can assist in the diagnosis, and the final diagnosis requires surgical specimen macroscopy and pathologic diagnosis.
Complications
(a) Infection and septicemia: Myoma infection is mostly a consequence of torsion of the tumor or acute endometritis, but hematogenous infection is extremely rare. Infection can sometimes be septic, and in a few cases, abscesses form in the tumor tissue. Intestinal adhesions occur after subplasmalemma torsion and can be infected by intestinal bacteria, and the inflamed myoma adheres to the uterine adnexa, causing septic inflammation. Submucosal myomas are most susceptible to infection and often coexist with acute endometritis after abortion or during the puerperium. Some are caused by injuries from curettage or obstetric surgery. Due to tumor protrusion or surgical trauma, the tumor envelope is often ruptured, and after the rupture, infection is likely to occur. It often causes severe irregular bleeding and fever. The decayed debris discharged loses color reaction due to necrotic tissue, so microscopic examination often cannot get results.
(b) Torsion: Subplasma leiomyosarcoma may twist at the tip, causing acute abdominal pain. In severe cases of twisting, if surgery is not performed immediately or if the tumor does not turn back on its own, it may form a free leiomyoma due to twisting of the tumor, as described above. A twisted fibroid can also drive the entire uterus, causing axial torsion of the uterus. The site of uterine torsion is usually near the endocervical canal, but this rarely occurs because the larger subplasma fibroids are attached to the base of the uterus and the cervical canal is long and thin. The symptoms and signs are similar to those of ovarian cystic tumor torsion, except that the mass is harder.
(c) Uterine fibroids combined with uterine body cancer: uterine fibroids combined with uterine body cancer accounts for 2%, which is much higher than uterine fibroids combined with cervical cancer. Therefore, menopausal patients with uterine fibroids who have persistent uterine bleeding should be alert to the presence of endometrial cancer at the same time. Before determining the treatment, diagnostic scraping should be done.
(iv) Uterine fibroids combined with pregnancy.
Treatment
(1) Follow-up observation: small and asymptomatic fibroids do not need treatment and should be reviewed regularly every 3 to 6 months. if the fibroids continue to increase in size or have obvious symptoms, treatment may be given. patients over 45 years of age with small fibroids and no symptoms may be observed regularly. the fibroids will stop growing and gradually shrink with menopause.
(2) Drug therapy: It is suitable for patients with uterus less than 2 months gestation size, with no obvious symptoms or who cannot tolerate surgery. It can reduce bleeding, shrink fibroids and relieve symptoms but not cure. The main drugs are testosterone propionate, gonadotropin-releasing hormone agonist (GnRH-a), triamcinolone and mifepristone, etc.
(3) Surgical treatment: Applicable to those with uterus larger than 2.5 months in size and without fertility requirement; secondary anemia caused by leiomyosarcoma and conservative treatment is ineffective; rapid growth of leiomyosarcoma with suspicious sarcoma-like changes; acute abdominal pain caused by twisted subplasma leiomyosarcoma tissues and red degeneration of leiomyosarcoma; symptoms of leiomyosarcoma compression; severe anemia caused by submucosal leiomyosarcoma. Surgery is considered for those who have one of the above conditions.
For young patients with fertility requirements, myomectomy can be performed, either open or laparoscopic depending on the specific situation; for patients with large fibroids and no fertility requirements, total hysterectomy or subtotal hysterectomy can be performed. Intraoperative examination of the resected specimen should be performed, and if the cut surface tissue is brittle and raw fish-like, it should be sent for rapid pathology to exclude uterine sarcoma.
In this case, the patient had a uterus the size of a third trimester pregnancy and presented with secondary anemia and pressure symptoms, and had no reproductive requirements, so total transabdominal hysterectomy was performed, which was consistent with the surgical indications.