Intraosseous Meningioma Masquerading as Fibrous Dysplasia

Background: Intraosseous meningiomas often display clinical and radiologic features that can be confused for fibrous dysplasia. Histopathology usually confirms the diagnosis. We present a case initially misdiagnosed as fibrous dysplasia by histopathology. Methods: A 58-year-old male presented with worsening proptosis and vision loss. He was previously diagnosed with fibrous dysplasia at an outside institution, with histologic confirmation of the diagnosis during orbital decompression. Results: On examination there was evidence of optic neuropathy and mild restriction of gaze. Imaging revealed a large ossified mass of the greater sphenoid wing. Craniotomy and surgical decompression resulted in improved vision and symptoms. Histopathology revealed meningioma with bony and dural components. Conclusions: This case emphasizes the need for a high level of suspicion and representative biopsies to reach prompt diagnosis of meningiomas in cases of recurrent or atypical fibrous dysplasia