Cystic lesions are frequent in the oral cavity. They are defined as a pathologic cavity with or without fluid or semi fluid material. The inflammatory lesions are more common, such as periapical cysts. These lesions are encountered in dental apex and the pulp necrosis is a very important cause of these cysts. The treatment can be conservative, like a biomechanic preparation of root, used when the lesion is localized, or the surgical treatment, like total or partial lesion removal. When the surgical treatment is realized, the marsupialization or decompression can be done before, and an enucleation after if necessary, and can be done a total enucleation that enucleate the lesion in one surgery. This technique is more used in big lesions. The aim of this case report is to show techniques of treatment of extensive periapical lesion, the advantages and disadvantages of each technique.

KEY WORDS: Periapical cysts; enucleation; marsupialization; bone lesion