Sino-orbital osteoma with osteoblastoma-like features: case reports.

Most of the orbital osteomas arise from the adjacent paranasal sinuses. Some of them may contain osteoblastoma-like areas and may be misdiagnosed as osteoblastoma, both radiologically as well as histopathologically. Sino-orbital osteomas with osteoblastoma-like features show a typical radiological appearance. They have a distinct zonal pattern, in which less dense osteoblastoma-like areas are located at the base of the lesion and dense mature bone is located at the periphery. These broad-based bone lesions also have a tendency for extracavitary polypoid growths from the paranasal sinus into the adjacent orbit. We report here the CT and MR imaging findings of three cases with sino-orbital osteoma with osteoblastoma-like features.