A gigantic ovarian fibroma: MR Imaging

Clinical History

Visible lower abdominal mass and abdominal and pelvic pain.

Imaging Findings

The patient was admitted to our hospital because she presented with a visible lower abdominal mass and abdominal and pelvic pain.
Transabdominal sonography showed a large mass with heterogeneous hypoechogenic pattern of unclear origin.
MRI was performed on multiple planes that showed, in right abdominal- pelvic region, a large multilobulated solid mass measuring 15 x 11,5 x 9 cm with inhomogeneous enhancement post-Gd administration. That mass was suspected to be of left uterine-adnexal origin, and make contact without infiltration with bowel -which appeared displaced- , urinary bladder , uterus and sacrum (Figs. 1-2-3); another finding was two right ovarian cystic masses of about 3 and 4.5 cm in diameter( Fig. 4 ) (associated with hydrosalpinx), as well as two uterine masses of about 3 and 7 cm in diameter. A total hystero-adnexectomy was performed (Fig. 5 ) and histological specimen were obtained which confirmed the diagnosis of fibroma of the left ovary.

Discussion

Ovarian tumors are classified as epithelial tumors, germ cell tumors, sex cord-stromal cell tumors, and metastatic tumors according to tumor origin. Characterization of an ovarian mass is important in preoperative evaluation of an ovarian neoplasm; therefore, familiarity with the clinical and imaging features of various ovarian tumors is important in determining the likelihood of a tumor benign or malignant. Fibroma and thecoma are forms of a spectrum of benign tumors. Lipid-rich thecoma demonstrates estrogenic activity and few fibroblasts. In contrast, fibroma has no thecal cells and demonstrates no estrogenic activity. These tumors occur in both pre-and post menopausal women. Fibroma is the most common sex cord tumor. It is composed of whorled bundles of cytologically bland, benign, spindle-shaped fibroblasts and collagen.
Ovarian fibromas are important from an imaging standpoint because they appear as solid masses, thereby mimicking malignant neoplasms. They are sometimes associated with ascites or Meigs syndrome .
Pelvic ultrasound (US) usually demonstrates a heterogeneous hypoechoic mass with posterior acoustic shadowing. However, a broad spectrum of US features is seen, and in most cases the appearance of the tumor is non specific .
CT shows a homogeneous solid tumor with delayed enhancement.
Because of their abundant collagen contents, these tumors have low signal intensity on T1-weighted MR images and very low signal intensity on T2-weighted images. These findings are relatively diagnostic for fibroma .Dense calcifications are often seen . Scattered high signal intensity areas in the mass represent edema or cystic degeneration.
Ovarian masses with fibrous components include fibroma, fibrothecoma, cystadenofibroma,and Brenner’s tumor. The fibrous components of these masses tend to have very low signal intensity on T2-weighted MR images.

Differential Diagnosis List

Final Diagnosis

Ovarian fibroma

URL:	https://www.eurorad.org/case/2627
DOI:	10.1594/EURORAD/CASE.2627
ISSN:	1563-4086