Hepatic endometriosis has an extremely rare occurrence characterized by the presence of ectopic endometrium in the liver. A diagnosis of hepatic endometriosis is established after surgery. A 51-year-old multiparous female was referred to our unit for investigation of a liver tumor. The patient reported a 6-month history of epigastric pain and vomiting. She had undergone conservative hysterectomy for uterine leiomyomas several years earlier. The results of liver function tests and the levels of tumor markers (CA 19.9, CEA, CA125, αFP) were normal. Radiological imaging (USS, CT and MRI) suggested the presence of liver cystadenoma, liver cystadenocarcinoma or cystic metastasis of the liver in the left liver lobe extending to the diaphragm with left hepatic vein compression. Laparotomy was performed. The intraoperative frozen sections suggested a diagnosis of endometriosis. Anatomical resection was performed, including left lobectomy with diaphragm resection. The final histology confirmed the presence of hepatic endometrioma without malignant transformation. Fourteen cases of hepatic endometrioma have been described in the medical literature. We herein report the 15th case. Making a preoperative diagnosis of hepatic endometriosis is very difficult, despite conducting a complete investigation, in the absence of clinical and radiological characteristics. The diagnosis is made according to a histological examination of the whole surgical sample.