Simple bone cyst of the mandible.

Simple bone cysts (SBCs) are nonneoplastic intraosseous cavities without an epithelial lining, surrounded by bony walls and either empty or containing liquid and/or connective tissue: they were first described in 1929 as a distinct entity of disease. The characteristic that distinguishes SBCs from true cysts is the absence of epithelial lining, that allow us to regard SBCs as pseudocysts.