Solitary bone cyst is a benign lesion of unknown origin up to the present date. Its origin is mainly attribute to trauma theory, caused by intra-osseous bleeding which prevents bone repair, causing thus a cystic cavity with serous hematic content lacking epithelial lining. In most cases, the lower jaw is the most affected. It is observed in patients with ages ranging 20-30 years, generally male, it is an asymptomatic, slow-growing entity which progresses toward the cortical plates; it can cause pathological mandible fractures. Its discovery is usually incidental during a radiographic examination. It appears as a radiolucent, unilocular ormultilocular image, with well -defined borders, lacking sclerotic areas. Additional tomography and magnetic resonance studies have revealed that these cavities are not necessarily taken up by fluids: there can be presence of gas, or they could be empty. A differential diagnosis must be established to discard dentigerous cysts, ameloblastoma, keratinizing odontogenic tumor, calcifying epithelial tumor or adenomatoid odontogenic tumor.