MRI features of ovarian fibromas: emphasis on their relationship to the ovary

To evaluate the magnetic resonance (MR) imaging features of ovarian fibromas, emphasizing the presence and shape of the ovary on the same side of the fibroma.

MR images from 23 patients with 24 histologically proven ovarian fibromas were reviewed by two radiologists. Eleven were pre-menopausal and 12 were postmenopausal. The presence and shape of the ovarian tissue on the same side of the fibroma were evaluated on T2-weighted MR images.

In 11 (46%) of the 24 ovarian fibromas, the ipsilateral ovary was detected on T2-weighted images. The ovary was crescent-shaped along the periphery of the fibroma in six (55%) of 11 fibromas and had a normal, oval shape in five (45%). Of these five tumours, the ovary was connected to the fibromas by a pedicle-like structure in three and was closely attached to the periphery of the fibromas in two. The ipsilateral ovary was detected in 10 (83%) of 12 fibromas in pre-menopausal patients, and in one (8%) of 12 fibromas in postmenopausal patients. There was a statistically significant difference (p=0.001) in the presence of detectable ipsilateral ovary between pre-menopausal and postmenopausal women.

Detection of the remaining ovary on the same side as the fibroma is not unusual on MRI, especially in pre-menopausal women, and the shape of the ovary may be normal in cases of fibromas with exophytic growth from the periphery of the ovary.