MR imaging evaluation of postmenopausal adnexal masses: correlation with final pathologic diagnosis

Adoption of transvaginal ultrasound in usual clinical settings allowed us to find asymptomatic adnexal masses more frequently in postmenopausal women. These masses were traditionally considered as the indication of surgical excision to determine histological diagnosis. Recently, if the appearance of that is simple cyst, conservative management may be acceptable because ultrasound benign diagnosis is proved to be reasonably reliable. We investigate here the reliability of benign diagnosis by MR imaging with gadolinium enhancement for both of simple and complex postmenopausal adnexal cystic masses.

We retrospectively examined the data of 121 postmenopausal patients who underwent surgery during a 3-years-period (from January, 2000 to December 2002) for adnexal mass under diagnosis of benign adnexal cysts based on MR imaging.

Pathological examination identified two cases of malignancy among 121 cases diagnosed as benign by MR imaging. Among the cysts that revealed a simple pattern by MR imaging, 64/66 cases (97.0%) were benign histology and among the cysts that showed a complex pattern by MR imaging, 55/55 cases (100%) were benign histology. Among the cysts with diameter less than or equal to 10cm, 48/49 simple cysts and 32/32 complex cysts were benign histology.

The diagnosis of benign adnexal mass in postmenopausal women by MR imaging was reliable. Conservative observation for postmenopausal patients of asymptomatic and small cysts under benign diagnosis based on MR imaging with gadolinium enhancement will be feasible even if the cysts appearances are complex, with careful follow-up program.