Massive growth of a meningioma into the brachial plexus and thoracic cavity after intraspinal and supraclavicular resection. Case report and review of the literature.

Extracranial meningiomas comprise approximately 2% of all meningiomas. Involvement of peripheral nerves by meningioma, either by a primary tumor or through secondary extension of an intraaxial lesion, is a much rarer entity; there have been only two reported primary brachial plexus meningiomas and one description of secondary involvement of the brachial plexus by extension of an intraaxial lesion. Although thoracic cavity meningiomas have been described in the literature, their pathogenesis is poorly understood. The authors present the case report of a 36-year-old man who was initially treated for a thoracic spinal meningioma that infiltrated the brachial plexus. After resection, progressive and massive growth with infiltration of the brachial plexus and pleural cavity occurred over a 5-year period despite radio- and chemotherapy. The case report is followed by a review of the literature of this rare entity.