Uterine prolapse occurs due to pelvic floor laxity which is most commonly seen in multiparous women of old age. Concurrent uterine prolapse and cystocele are common by their similar underlying etiology. On images, uterine prolapse is diagnosed by identifying a prolapsed uterus into the perineal area rather than the normal uterine fossa location.

Uterine myomas are located in the myometrium of the uterus. Uterine myomas could be categorized by their locations as submucosal, intramural, and subserosal myomas [1]. Submucosal myomas protrude internally and cause deformed uterine cavity. Subserosal myomas protrude externally with a resultant lobulated uterine surface. On images, uterine myomas are diagnosed by confirmation of their anatomical locations as well-defined masses within the myometrium and their typical imaging findings as well as the presence or absence of calcifications and degenerations within the tumors. Ultrasound is usually the first-line imaging modality for uterine myomas [1]. On ultrasound, a uterine myoma usually presents as a hypoechoic or heterogeneous mass of round or oval shape relative to the normal myometrium [1]. In the absence of calcifications and degeneration of uterine myomas, they show similar density to that of normal uterine myometrium on unenhanced computed tomography (CT) and homogeneously hypodense to the uterus on enhanced CT. Calcification is a specific sign of uterine myomas but only found in 10 % of patients [2]. Plain radiographs of the kidney, ureter, and bladder, excretory urography, or CT could detect a calcified uterine myoma by its typical calcified pattern and anatomical location. On MRI, T2-weighted images are most useful for demonstrating uterine myomas which are typically shown as homogeneous low signal intensity masses [1, 2]. Uterine myomas are usually well-defined masses on MRI. Uterine myomas with degenerative changes show heterogeneous density on CT and heterogeneous signal intensity on MRI [2].

Adenomyosis is defined as the presence of ectopic endometrial tissue in the myometrium. Adenomyosis is categorized into diffuse and focal forms. Focal adenomyosis shows imaging finding of a uterine mass on ultrasound, which could be indistinguishable from uterine myomas. Diffuse adenomyosis results in uterine enlargement with thickened transitional zone more than 12 mm as shown on T2-weighted image of MRI [1]. Focal adenomyosis shows a uterine mass with an ill-defined border relative to normal uterine tissue, which contains some small hyperintense foci on T2WI, representing hemorrhage or endometrial tissue [1].

Uterine leiomyosarcoma is an uncommon uterine malignancy. Uterine leiomyosarcomas could not be reliably differentiated from leiomyomas with degenerative changes by imaging features on ultrasound (US), computed tomography (CT), or magnetic resonance image (MRI). However, CT could assess metastasis from a uterine leiomyosarcoma [1]. On MRI, a uterine mass in the myometrium presenting as huge size and with heterogeneous signal intensity and hemorrhage and necrosis should alert the readers of the possibility of a uterine leiomyosarcoma [2]. A close follow-up of the patients by images is necessary because the diagnosis of a uterine leiomyosarcoma is sometimes established after occurrence of metastasis. It is because of the difficulty of establishing histological diagnosis to some uterine leiomyosarcomas at the time of myomectomy or hysterectomy and some leiomyomas undergoing malignant transformation.

Imaging provides preoperative staging and helps select treatment planning for endometrial carcinomas [3]. Endometrial carcinoma is a common malignant tumor of the uterus [3]. The diagnosis of endometrial carcinoma basically relies on histological examination, and its most common histological type is endometrioid type [3]. Magnetic resonance imaging (MRI) is the most accurate for staging of endometrial cancers. MRI could evaluate the presence and depth of myometrial invasion as well as cervical invasion by endometrial cancer [3]. Irregular interface between endometrial carcinoma and adjacent myometrium indicates myometrial invasion [3]. Unenhanced T2-weighted image and enhanced dynamic images on T1-weighted fat-suppressed images are most valuable in assessing myometrial invasion [3]. The uterine cervix stroma loses its normal low signal intensity and is replaced by intermediate signal intensity mass suggesting uterine cervix invasion by endometrial carcinoma [3]. Transvaginal ultrasound is usually the first-line imaging tool for evaluating patients with clinical suspicion of endometrial carcinomas, who usually present with postmenopausal vaginal bleeding [3]. Endometrial thickness of 5 mm on transvaginal ultrasound has been proposed as an imaging criterion for diagnosing endometrial carcinomas [3]. However, MRI has better performance for evaluating myometrial invasion by endometrial carcinomas than transvaginal ultrasound [3]. The use of computed tomography (CT) should be reserved for advanced endometrial cancers [3]. It is because CT has poor performance in assessing myometrial and uterine cervix invasion by endometrial cancer [3]. However, CT could diagnose bladder invasion, pelvic wall invasion, lymph node metastasis of the abdomen and pelvic cavity, or distant organ metastasis by endometrial carcinomas [3].