Prolapsed submucosal uterine fibroid
Surgical excision of this prolapsed intracavitary mass was performed and histopathology revealed fibroid with areas of cystic degeneration. Final diagnosis: submucosal pedunculated prolapsed intracavitary fibroid.
Fibroids are the commonest benign uterine tumors, and may present as submucosal (under the mucosa), intramural (within myometrium; most common), sub-serosal (under the serosa), intra-cavitary (submucosal pedunculated), extra-uterine (broad ligament, cervical, parasitic) in locations. Uterine contour abnormalities, endometrial distortion, and mass effect may be seen depending upon the location of the fibroids.
MRI is usually indicated for complex or problem-solving cases. As in our case, ultrasound was limited as the patient could not hold urine and adequate bladder filling was limiting adequate transabdominal sonographic evaluation. Ultrasound appearances are variable depending on the leiomyomatous tissue components (smooth muscle and variable fibrous connective tissue) and areas of degeneration, but fibroids usually are hypoechoic or heterogeneous in echogenicity.
Fibroids usually appear as low to intermediate signal intensity on T1 (compared to normal myometrium) and low on T2WI, often showing areas of high T2 signal (cystic degeneration; no enhancement) or low T2 signal (hyaline degeneration) 1. Variable or gradual (in myxoid degeneration) contrast enhancement may be seen. A high signal T1 rim may be seen that represents red degeneration (usually occurs during pregnancy). Diffusion restriction may be seen, that represents cellularity (cellular fibroid).
Differential possibilities include prolapsed endometrial polyp and endometrial carcinoma. Endometrial polyps are usually T1 isointense to the endometrium, hypointense on T2 (surrounded by hyperintense fluid and endometrium), and show homogeneous or heterogeneous contrast enhancement 2. Endometrial carcinoma shows similar T1 and T2 signal as of polyp, however, demonstrates relatively less contrast enhancement than normal endometrium, besides diffusion restriction and invasion or extension depending on stage 3.
Sometimes diagnosis remains difficult and surgical excision /histopathology is needed for a conclusive diagnosis.