MRI diagnosis of ovarian fibrothecomas: tumour appearances and oestrogenic effect features

To study MRI diagnosis of ovarian fibrothecomas.

MRI appearances of 27 ovarian fibrothecomas 26 female patients confirmed by surgical pathology were retrospectively reviewed and correlated with clinical and histological findings.

Most patients were post-menopausal females 73.1% (19/26) of cases. 38.5% (10/26) of patients showed an elevated serum carbohydrate antigen 125 (CA-125) level (>35 U ml(-1)). On MR T2 weighted imaging, 3 distinct features were revealed. (1) Homogeneous hypointense masses in 25.9% (7/27) cases. (2) Heterogeneous tumours with mostly isointense and few patchy hyperintense areas in 51.9% (14/27) cases. (3) Heterogeneous tumours with predominantly hyperintense and few isointense parts in 22.2% (6/27) cases. On T1 weighted imaging, all the fibrothecomas turned out to be homogeneous masses except six cystic degeneration cases. After contrast, 70.4% (19/27) tumours showed homogeneous mild enhancement in all phases. Beyond the tumours, endometrial abnormality and uterus enlargement were found in 38.5% (10/26) and 15.4% (4/26) patients, respectively. Ascites were seen in 53.8% (14/26) patients. There was a statistically significant difference among the 3 T2 weighted image features (F = 7.024; p = 0.003) in terms of the size of fibrothecomas. The cystic tumours also had the tendency to show the ascite condition (p = 0.002) as well as elevated serum CA-125 levels (p = 0.014). Vimentin was positively stained in 10 (76.9%) of 13 cases who underwent the immunohistochemical analysis.

MRI has the superiority to show the distinct appearances of tumours as well as their functional features according to oestrogenic effect.

This study describes the unique features of fibrothecomas on MRI on a relatively large series of patients with tumours and the indirect oestrogenic effect findings.