Ovarian fibroma (fibrothecoma) with extensive cystic degeneration: unusual MR imaging findings in two cases.

Two cases of ovarian fibroma (fibrothecoma) with extensive cystic degeneration are described. One case revealed a large multiloculated cystic mass with a small solid part. Each locule showed variable signal intensity on both T1- and T2-weighted magnetic resonance (MR) images. The other case revealed a parviloculated cystic mass with a small solid part. In both cases, the solid parts were located at the periphery of the mass and showed distinct low signal intensity on both T1- and T2-weighted MR images and slight enhancement. It should be noted that ovarian fibromas (fibrothecomas) with extensive cystic degeneration are a rare exception to the rule that solid components in a cystic adnexal mass imply malignancy.