Abstract: The author reports a case of endometriosis with unusual imaging findings. ¹⁸F-fluorodeoxyglucose (FDG) PET/CT imaging revealed extensive involvement of ectopic endometrial lesions in the bilateral adnexa, intestines, and mesenteric lymph nodes. The imaging features resembled those of malignant ovarian tumors, making differential diagnosis challenging. The authours intend to analysis the case and review related relevant literature in order to deepen the understanding of the imaging characteristic of endometriosis by ¹⁸F-FDG PET/CT and provide a reference basis for the differential diagnosis of similar complex cases.