There are various types of uterine lesions, with the most common being tumors or tumor like lesions that occur in the endometrium, as well as myometrial tumors. Common uterine lesions can be divided into benign and malignant lesions. Common benign lesions of the uterus include endometrial hyperplasia, endometrial polyps, uterine fibroids, etc. Common malignant lesions of the uterus include endometrial cancer, cervical cancer, etc. Below are some common uterine lesions and MRI manifestations.
Endometrial hyperplasia is more common in young women and can also be seen in perimenopausal or postmenopausal women. Long term estrogen stimulation is the main high-risk factor. Most patients respond well to ovulation inducing drugs or progesterone treatment, while a few require hysterectomy. Menstrual abnormalities are the main symptoms, often manifested as irregular vaginal bleeding and postmenopausal bleeding. Long term anovulation caused by endocrine disorders can lead to infertility. Gynecological examinations often show no positive signs. The main manifestation of MRI is diffuse and uniform thickening of the endometrium, with clear boundaries, and focal endometrial thickening is less common. The T2WI signal is close to the endometrium, with intact binding bands. Both DWI and ADC images show slightly high signal intensity, with gradual mild to moderate enhancement. Small cystic lesions can be seen. The endometrium is lower than the uterine muscle layer in the early stage and slightly higher than the muscle layer in the delayed stage. The boundary between the thickened endometrium and the muscle layer is clear.
Endometrial polyps are common benign lesions in women, characterized by excessive proliferation of local endometrial glands, stroma, and accompanying blood vessels protruding into the uterine cavity. It can occur at any age after puberty, but is more common in women over 35 years old. It is usually related to factors such as inflammatory stimulation, high estrogen levels, and pathogen infection. Endometrial polyps can be single or multiple, with a diameter generally less than 1cm, and a very small number of polyps are larger, even filling the entire uterine cavity. Large volume or multiple occurrences often manifest as menstrual irregularities, abnormal vaginal discharge, and irregular bleeding. MRI findings may not be displayed when the polyp volume is small. When the polyp volume is large, MRI shows a circular or elongated, tongue shaped lesion in the uterine cavity. Clear boundaries and regular forms. The signal is uniform or uneven, often showing equal T1WI and slightly higher T2WI signal. Combine with complete tape. Some polyps show low signal fibrous nuclei on T2WI, and sometimes higher signal cystic areas on T2WI. DWI has no obvious diffusion limitation. When combined with bleeding, the signals are mixed. Enhanced scanning shows lesions as papillary enhancement nodules in the uterine cavity, which often exhibit progressive enhancement and are equal to or slightly higher than the uterine muscle layer.
Uterine leiomyoma, also known as uterine fibroid, is the most common benign tumor of the uterus, composed of smooth muscle and fibrous stroma arranged in a spiral pattern, with a false capsule on the outside. According to its location, it can be divided into: inter wall type; Submucosal type; Subserosal type; Ectopic type with pedicle, the most common one is intramural fibroids. Often multiple, of varying sizes, commonly seen in the uterine body. Fibroids have variability, including hyaline, mucinous, and adipoid changes, as well as necrosis, bleeding, and calcification. It usually occurs in 30-50 years old, mainly manifested as menorrhagia, long menstrual period, short interval, infertility, habitual abortion, compression symptoms (such as urinary retention, constipation) when the tumor is large, and acute abdominal pain can be caused when the pedicled tumor turns. The MRI manifestations of uterine fibroids are T1WI tumor signal similar to uterine muscle, T2WI tumor with low signal and clear boundaries; Most fibroids have uniform internal signals and no diffusion restriction on DWI. When degenerated or accompanied by necrotic cystic calcification, the signal is uneven, with the cystic area showing low signal on T1 weighted images and high signal on T2 weighted images. Calcification is a double low signal. Among them, special types of cellular richness can be manifested as diffusion limited DWI. Uterine fibroids can be significantly and uniformly enhanced, consistent with or slightly lower than the muscle layer, and may be unevenly enhanced during degeneration. The cystic changes, calcification, and other parts do not strengthen.
Endometrial cancer is a common malignant tumor in women. Its incidence rate is second only to that of cervical cancer, and most of it is adenocarcinoma. The focus starts in the endometrium, then invades the muscularis, and finally reaches the parauterine tissue, bladder and adjacent bowel. The peak age of onset is 55~65 years old. Obesity, diabetes and hypertension are risk factors. The main symptoms include irregular vaginal bleeding, vaginal discharge, abdominal pain, etc. MRI findings: Endometrial cancer is commonly characterized by diffuse irregular thickening of the endometrium, widening and bulging of the uterine cavity, presenting as nodules or polyps. On T1WI, most tumor signals are similar to those of the uterine muscle layer (except for bleeding, which can cause signal elevation). On T2WI, the tumor shows high or equal signal intensity. Meanwhile, the integrity of the binding band is an important indicator for evaluating whether the muscle layer has been invaded. After enhanced scanning, the degree of lesion enhancement was significantly lower than that of the junction zone and muscle layer, showing mild uneven enhancement, and the enhancement curve showed an outflow or plateau pattern. Endometrial cancer DWI shows high signal intensity, with ADC values significantly lower than normal endometrium and benign lesions. Characteristics of lymph node metastasis: round and large, with a short diameter greater than 10mm, rough edges, and enhancement characterized by consistent, uniform, or circular enhancement curves (excluding tuberculosis and fungal infections). DWI imaging: diffusion limited, significantly reduced ADC value, most valuable for diagnosis. MRI is the most valuable diagnostic tool for determining tumor range and staging, observing therapeutic efficacy, and determining tumor recurrence. It is a routine preoperative examination for endometrial cancer and helps in the selection of clinical treatment plans and prognosis assessment.
Cervical cancer is the most common malignant tumor in the female reproductive system, and its causes are related to early sexual intercourse, multiple pregnancies, HPV infection, and other factors. The vast majority of cervical cancer is squamous cell carcinoma, accounting for about 90%, followed by adenocarcinoma or adenosquamous cell carcinoma, accounting for about 10%. It mostly occurs at the junction of squamous epithelium and columnar epithelium. Metastasis mainly occurs along lymphatic pathways, while hematogenous metastasis is rare. The MRI manifestations of cervical cancer include increased volume and irregular morphology of the cervix. On T1WI, the tumor appears as a slightly low or iso signal mass, while on T2WI, it has a moderate to slightly high signal mass, which is higher than the cervical stromal signal. DWI: diffusion limited, localized high signal. ADC value lower than normal cervical stromal mucosa; After enhancement, mild to moderate uniform or uneven enhancement can be seen, slightly lower than the uterine stroma, and the enhancement curve shows an outflow type and plateau type.