Internuclear ophthalmoplegia and "optic neuritis": paraneoplastic effects of bronchial carcinoma.

A 56-year-old man developed bilateral internuclear ophthalmoplegia and "optic neuritis" as remote effects of a bronchial carcinoma. These clinical findings correlated pathologically with secondary demyelination of the medial longitudinal fasciculus and with round cell infiltration and adhesive arachnoiditis of the optic nerve. There was no evidence of CNS metastasis. "Optic neuritis" and internuclear ophthalmoplegia may be paraneoplastic effects of systemic cancer.