Malignancy in endometrioma, how to spot it?
Type:Scientific Electronic Presentation
Authors: Helena Paixão, Teresa Margarida Cunha
Keywords:Endometrioma, endometriosis-related malignancies, malignant ovarian endometrioma, endometriosis-related extraovarian malignancy

To analyse histologically proven endometriosis-related malignancies (ERM) in order to recognize their main locations and identify their features of malignancy on MRI.

Material and methods

A 5-year retrospective study of all ERM cases of our oncological referral center was made and we found 14 cases of endometriosis-related malignancies.

We described the sites of proven ERM and we identified the main features of malignancy in endometriosis on MRI.

We used the Intelispace software to determine mural nodules enhancement.

Patients without histological confirmation were excluded from the study.


From a total of 14 cases, only 11 had MRI, and only 9 MRI had gadolinium-based contrast administration.

We separated the cases of ERM into ovarian (57.1%) and extra-ovarian malignancies (42.9%) and we will separately discuss their features according to literature, giving illustrative images.


MRI features of malignant ovarian endometrioma (MOE)

Solid enhancing mural nodules

Studies have shown the most sensitive MR imaging feature for diagnosis of malignancy in an endometrioma is the presence of an enhancing mural nodule.

The nodules are frequently iso to hypointense on pre-contrast T1-weighted sequences and homogeneously or heterogeneously enhance on T1-weighted post-contrast sequences. The signal intensity on T2-weighted sequences is... more

Figure 1: Malignant MRI feature of solid enhancing nodules. Axial images of the pelvis show a small enhancing, solid lesion arising from the right ovary (circle). The solid nodule is primarily T2 and T1 hypointense (upper images) with restricted diffusion (middle images) and enhancing after contrast administration.
Figure 2: MRI using the Intelispace software to determine mural nodules enhancement and to better differentiate the solid mural nodules from the surrounding T1 bright haemorrhagic fluid.


Radiologists should be familiar with the features of ERM, as they represent a disease with different management and, in fact, with a better prognosis than the more common epithelial ovarian tumours.  

Diagnosing ERM may be challenging but an optimized MR protocol, including dynamic subtraction images, is key to achieving it. In addition, a high index of suspicion is required since the malignant transformation of endometriosis is rarely associated with lymphadenopathy or peritoneal implants.

Our results support that ERM are more common in the ovaries and enhanced mural nodules are the most sensitive feature on MRI for diagnosing malignancy in an endometrioma.

Extraovarian endometriosis-related malignancies’ distribution usually mirrors the sites of endometriotic implants, with a higher prevalence on rectovaginal sites, which was also not discordant in... more