The MRI findings in a case of ovarian mucinous borderline tumor mimicking a serous surface borderline tumor.

Exophytic papillary growth from the surface epithelium is one of the features suggesting serous surface borderline tumors of the ovary in which magnetic resonance imaging (MRI) typically shows a hyperintense papillary mass with a hypointense internal branching structure on T2-weighted images. We herein report a case of an endocervical-like mucinous borderline tumor of the ovary, which showed an exophytic papillary growth pattern on MRI as well as pathology. Such a growth pattern is known to be characteristic of serous borderline tumors, but it should be noted that it could also be a finding in mucinous borderline tumors.