Solitary bone cyst of the jaws

Solitary bone cyst is a radiolucent lesion classified as a pseudocyst with a variety of reported shapes including round, oval, and irregular. In the long bones, a truncated cone shape has been described, and the fallen trabecula sign is seen in association with pathologic fracture. The purpose of this study was to classify and document the various shapes, to describe the width versus height dimensions of jaw SBCs, to determine the identifying signs of trauma, and to evaluate other reported radiographic features. Radiographs of 44 SBCs in 43 patients were studied. Sixty-four percent demonstrated the cone shape, and four subtypes of this shape were identified. Other shapes included oval (16%), irregular (16%), and round (4%). Radiographic signs of trauma were observed in 28% of the cases. No evidence of the "fallen trabecula sign" was found in this series.