Endometriosis MRI: Atypical cases, pitfalls and mimics

Endometriosis is a common but often underdiagnosed chronic gynaecological disease. Endometriosis mimics other diagnoses both clinically and radiographically, presenting a diagnostic challenge. Endometriosis can be categorised as superficial pelvic endometriosis, deep invasive endometriosis (DIE) or endometrioma. Endometrioma and DIE, including polypoid endometriosis, can masquerade as invasive neoplasms. Endometriosis can be misdiagnosed in less common locations or during pregnancy. Ultrasound is the initial investigation for endometriosis; however, MRI is advantageous in providing a larger field of view for increased detection of nodules as well as distinguishing malignancy with greater certainty. This review highlights endometriosis mimics, pitfalls and atypical cases on MRI.