Background &objectives: Echinococcosis, referred to as hydatid disease or hydatidosis, is a parasitic disease caused by larval stage of Echinococcus granulosus. In the life cycle of this parasite, dogs and other carnivores are definitive hosts and herbivores are intermediate hosts. Humansin this cycle may incidentally involve by ingestion of parasite eggs and play as intermediate host. Hydatid disease can involve any organ but liver and lung are the most commonly affected organs and kidney, brain, heart, bone may also be affected to a lesser degrees. Cerebral hydatid cyst occurs in about 2% of all echinococcosis cases. In this paper we report two cases of cerebral echinococcosis in whom diagnoses were made based on MRI findings and confirmed by pathology reports after surgery.

  First Case Report: The first case was a 30 years old man who was admitted after an episode of generalized tonic-clonicseizure. The MRI imaging performedand patient underwent surgery with diagnosis of a right frontal cystic lesion. The patient was improved progressively and there was no seizure attack and recurrence during 18 months follow up period.

  Second Case Report: The second case was a 28 years old woman presented by headache and abnormal behavior. MRI of this patient revealed a large cystic lesion in left frontal lobe and then underwent surgery. No complication was seen during postoperative period. The headache and behavioral disorder were improved completely and there was no sign of recurrence during 18 months follow up period.

  Conclusion: Hydatid cyst should be considered as a differential diagnosis of cystic brain lesions in endemic areas. Although hydatid cyst is a benign lesion but surgical removal of it without rupture is very important for prevention of probable future complications.