Meningeal carcinomatosis with blindness.

A 53-year-old man had bilateral blindness secondary to meningeal carcinomatosis from pulmonary adenocarcinoma. Histopathologic examination of the visual system showed extensive infiltration of the arachnoid of the proximal optic nerves and chiasm, with minimal invasion of the optic nerves themselves. The visual pathways within the cerebral cortex were not affected.