METASTASIS OF ADENOCARCINOMA OF THE LUNG TO OPTIC-NERVE SHEATH MENINGIOMA

A 71-year-old woman developed chronic progressive visual loss in the r ight eye and computed tomographic scan showed enlargement of the intra orbital optic nerve consistent with optic nerve sheath meningioma. Ove r 12 years, the contralateral optic nerve was not clinically affected, and serial neuroradiologic imaging showed no evidence of intracranial tumor extension. Death occurred from metastatic adenocarcinoma of the lung 14 years after initial visual loss. Examination of the postmorte m specimen of optic nerve and chiasm revealed extradural extension of meningioma with spread to the region of the optic chiasm and hypothala mus. A large focus of metastatic adenocarcinoma was present within the intraorbital portion of the meningioma. Carcinoma metastatic to intra cranial meningioma is rare; to our knowledge, this is the first report ed case in an optic nerve sheath meningioma. Neuroimaging may be inade quate to predict the value of tumor excision in preventing intracrania l spread of optic nerve sheath meningioma.