About 10% of all intracranial meningiomas occur in the posterior fossa and over 70% are found in women . A higher frequency in children was described which has not been confirmed in more recent studies . The cells of origin are probably the arachnoid cell clusters found embedded in the dura mater of the basilar regions, near the exit foramina of the cranial nerves, especially of the trigeminal and vestibuloacoustic, and in relation to the dural sinuses, especially the inferior petrosal and sigmoid [67, 303]. Meningiomas of the posterior fossa are usually at least 3 or 4 cm in size when diagnosed, and their precise site of origin can be difficult to determine. In some cases a relatively small base 1–1.5 cm in diameter is definable which contains the vascular pedicle, although usually this is surrounded by a wider area of secondary attachment which also may be traversed by vessels [54, 189, 251, 303].
KeywordsLymphoma Peri Myeloma Meningioma Hydrocephalus
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