Endometriosis: imaging spectrum of unusual locations and atypical presentations

Endometriosis is a chronic, estrogen-dependent inflammatory disease defined by the presence of endometrial-like tissue outside the uterus, affecting approximately 10% of women of reproductive age as well as a notable proportion of adolescents and postmenopausal patients. Although traditionally considered a pelvic disorder, it is increasingly recognized as a multisystem condition with a broad spectrum of extrapelvic locations and atypical clinical and imaging presentations, which contribute to significant diagnostic delay. This review provides a comprehensive overview of the imaging spectrum of endometriosis beyond the pelvis, emphasizing the central role of magnetic resonance imaging (MRI) in lesion detection, characterization, and preoperative mapping. Particular attention is given to the diverse manifestations of extrapelvic disease, including gastrointestinal, genitourinary, thoracic, musculoskeletal, and neural involvement, each of which may present with nonspecific or misleading findings and mimic other pathological entities. Additionally, uncommon presentations such as infection, malignant transformation, and decidualization, as well as variations across different patient populations, further increase diagnostic complexity. Recognizing these patterns and understanding their imaging features are essential to avoid misdiagnosis and delays in care. A systematic approach combining clinical suspicion, tailored imaging protocols, and structured reporting is key to improving diagnostic accuracy and guiding appropriate management. Greater awareness of the multisystem nature of endometriosis is crucial to optimize patient outcomes and reduce the burden of this frequently underrecognized disease.