PRIMARY INTRAOSSEOUS MENINGIOMAS

Purpose: A retrospective study was performed to evaluate the clinical, radiological and histological findings of 14 intraosseous meningiomas . Material and Methods: 14 histologically proved intraosseous meningio mas were studied with plain skull film and CT. Pathological records we re reviewed. Results: We found 9 calvarial cases and 5 spheno-orbital ones. The most common symptom in the calvarial cases was a lump in the scalp, and in the spheno-orbital lesions it was exophtalmos. Hyperost osis was present in all 5 spheno-orbital cases and in 3 out of the 9 c alvarial ones; in the other 6 cases it had a mixed pattern. Enhanced d ura was present in 3 calvarial cases and in 2 sphenoidal ones. Dura wa s involved in 5 cases: 2 with inflammatory changes, 2 with a minimal i ntradural tumour and one with a subdural tumour. Conclusion: CT better detected both the bony reaction and the intraosseous extension of the tumour. The dural changes were not specific of tumoural involvement. The differential diagnosis comprises: fibrous dysplasia, osteoma, blas tic metastasis and mainly meningioma en plaque (MEP). Comparing our fi ndings with other series, we noticed that in some cases the term MEP w as used for similar cases. As the name MEP is merely descriptive and b oth entities share a larger number of similarities than differences, w e believe that a differentiation between hyperostotic en plaque mening ioma and intraosseous meningioma can hardly be made.