Hydatidosis due to Echinococcus granulosus is an endemic parasitic zoonosis characterized by worldwide distribution particularly in Mediterranean countries. The most commonly involved anatomical locations are the liver and lung. Occasionally the cyst may progressively increase in size, mimicking gross ascites or intrabdominal tumor. Herein, are reported a case of a 40-year-old patient with a giant exophytically expanded hepatic echinococcus cyst, misdiagnosed as an abdominal malignancy during formal investigation. The patient was admitted to the hospital complaining for mild diffuse abdominal tenderness, moderate abdominal pain, nausea, diarrhoea, and vomiting. A CT scan revealed the presence of a giant abdominal mass 25 x 21 x 14 cm, resembling a tumor, adherent to the liver edges and parietal peritoneum, displacing intestinal loops. During the ensuing days the patient's clinical condition worsened, and he became febrile. Exploratory laparotomy was performed, and an exophytically grown giant liver hydatid cyst was removed, despite the radiological findings and the preoperative clinical suspicion.