Multimodality Imaging of Extra-Ovarian Lesions Simulating Ovarian Masses

Background: The female pelvis is a complex anatomical region where numerous extra-ovarian pathologies closely mimic ovarian masses. Misdiagnosis can lead to unnecessary surgery and delayed treatment. Accurate multimodality imaging interpretation is essential for appropriate patient management.
Objective:  To describe the imaging characteristics, clinical context, and key differentiating features of the full spectrum of extra-ovarian pelvic pathologies identified in a retrospective single-center series, illustrating selected cases with representative imaging findings.
Methods: Retrospective study of 241 patients presenting with a pelvic mass on ultrasound (US), computed tomography (CT), and/or magnetic resonance imaging (MRI) at the Radiology Department of Hassan II University Hospital, Fez, Morocco, over a three-year period (January 2023–December 2025). Cases were classified based on histopathological and/or radiological findings.
Results: Twenty distinct extra-ovarian etiologies were identified across 241 cases, including tubal pathology (hydrosalpinx/hematosalpinx n=13, pyosalpinx/tubo-ovarian abscess n=23), adnexal ectopic pregnancy (n=13), adnexal torsion (n=27), peritoneal inclusion cyst (n=14), uterine vasculature (n=9), leiomyoma FIGO 7 (n=17), peritoneal carcinomatosis (n=12), peritoneal tuberculosis (n=8), appendicitis/diverticulitis (n=21), appendiceal mucocele (n=10), GIST (n=5), sigmoid tumor (n=7), necrotic lymphadenopathy (n=11), lymphoma (n=7), sarcoma (n=3), neurogenic tumors (n=4), pelvic pheochromocytoma (n=1), hematoma (n=23), and lymphocele (n=13). MRI was the definitive problem-solving modality in the majority of cases.
Conclusion: A systematic multimodality imaging approach combining anatomical compartment analysis, specific imaging signs, and clinical correlation enables accurate differentiation of extra-ovarian pelvic pathologies from true ovarian masses, preventing misdiagnosis and guiding optimal management. MRI remains the superior problem-solving tool in this context.