What are the radiological features and common sites of involvement for cerebral echinococcosis, and how can it be differentiated from other cystic brain lesions?

Cerebral echinococcosis, caused by the Echinococcus granulosus tapeworm, typically presents with solitary, unilocular cysts that are large, round, and smoothly marginated, often located in the supratentorial region within the middle cerebral artery territory. Key diagnostic features include the presence of a well-defined cyst with a possible detached endocyst (water-lily sign) and lack of significant surrounding edema. Clinical pearls include considering echinococcosis in patients with a history of exposure to dogs or endemic areas. Common pitfalls include confusing these cysts with other cystic lesions like arachnoid cysts or cystic tumors, which may have different clinical and imaging characteristics.