Non-puerperal uterine inversion is a rare condition that can be presented due to gravitational mass effect of tumors. Rare causes include uterine tumors such as sarcomas, carcinomas and mostly benign conditions such as leiomyomas as in our case (
1,
2). Diagnosis of non-puerperal uterine inversion can be difficult as they may not present with common typical symptoms (
3). Clinical differential diagnosis of uterine inversion is troublesome even if the fundal depression can be palpated on rectal examination because of rectal condition and its presence may be missed until the time of surgery. Radiological evaluation is essential for differential diagnosis of the clinically examined mass and the uncommon symptoms. As in our case, it was difficult to differentiate the actual origin of the giant mass with sonography Transvaginal clinical and sonographical examination was not possible. In transabdominal ultrasonography, the Y shape fundal indentation and depressed longitudinal groove extending from the uterus to the center of the inverted portion in every case is not recognized (
4). MRI is the best radiological modality not only for the correct diagnosis, but also to delineate the lesion with neighbor structures (
5). Computed tomography is not used as the first line examination in such pelvic masses, but it can be an option in conditions that MRI is not possible. Contrast enhanced examination is favored for delineation.
Standard pelvic MRI protocol with axial and sagittal T2-weighted scans revealed V-shaped uterine cavity and an inverted uterine fundus, and the uterine fundus was lined by a hyperintense endometrium surrounded by a hyperintense rim layering “bull’s-eye” configuration with the adjacent mass. These images are the indicative signs for uterine inversion. As well as revealing the uterine inversion, magnetic resonance imaging can depict the stage of morphologic changes of the uterus, the origin, extension, signal, and contrast enhancement properties of the mass, and the accompanying features of lesion invasion and pathological status of the lymph nodes.
A classification of genital inversion has been described and treatment of the inversion is suggested according to the stage and associated pathology. In stage 1, inversion of the uterus is intrauterine (incomplete) and the fundus remains within the cavity; stage 2, complete inversion of the uterine fundus through the fibromuscular cervix; stage 3, total inversion; the fundus protrudes through the vulva; stage 4, the vagina is also involved within total inversion. While stage 1, repositioning of the fundus could be tried for treatment, for stages 2-4, hysterectomy should be an option and should be discussed with the patient if childbearing is not an issue (
6,
7). Eventually, radiologic evaluation is the key for stage definition and pre-operative decision-making. Radiologic algorithm should be followed from simple to detailed. Ultrasonography is the first-line evaluation method and MRI should be followed for insufficient and undetailed imaging as in our case. In the absence of a mass lesion, inversion is easily depicted in the transabdominal view. Transvaginal approach can be used for more complex cases in the early stages of the disease. Late stages of the disease and accompanying mass lesion to inversion often require MR imaging.
In conclusion, although being a rare entity, uterine inversion associated with giant pelvic mass can be easily recognized radiologically. If inversion occurs along with a giant mass, necrosis, infection, and severe anemia are evident and should be treated to avoid complications. The viability of the uterus is crucial for prognosis especially for younger patients. Therefore, the treatment should be arranged as soon as possible. This condition has to be clearly visualized for preoperative planning and also diagnostic suspicion of a malignant uterine tumor should be excluded. In our case, MRI was performed complementary to proper ultrasonographic evaluation. In this context, again, MRI is a valuable problem-solving tool for preoperative diagnosis of uterine inversion.