Most grade 1 endometrioid cancers are confined at the time of diagnosis and confer a good prognosis. The author reports the case of a 46-year-old Caucasian woman, referred to the gynecologist for anemia and increased volume of the abdomen. Computed tomography scan showed a large intra-abdominal cystic mass, originating from ovary. The tumor measured 22 cm and was perforated. The patient underwent radical surgery. Histology confirmed epithelial tumor type endometrioid, very good differentiated, grade 1 adenocarcinoma. Adjuvant chemotherapy was administered. At 12 months post-presentation, imaging did not show any sign of recurrence and the patient remains under surveillance.