Pictorial essay: MRI evaluation of endometriosis-associated neoplasms.

Endometriosis is a frequent pathology mostly affecting women of young age. When typical aspects are present, the diagnosis can easily be made at imaging, especially at MRI. Transformation of benign endometriosis to endometriosis-associated neoplasms is rare. The physiopathology is complex and remains controversial. Endometrioid carcinoma and clear cell carcinoma are the main histological subtypes. Our goal was to review the main imaging characteristics that should point to an ovarian or extra-ovarian endometriosis-related tumor, especially at MRI, as it may be relevant prior to surgical management.Key points• Transformation of benign endometriosis to endometriosis-associated neoplasms is rare.• MRI is useful when displaying endometriosis lesions associated to an ovarian tumor.• Subtraction imaging should be used in the evaluation of complex endometriomas.