Abstract
A 43-year-old woman presented with bilateral internuclear ophthalmoplegia (BINO) and then developed bilateral ptosis. Neuropathologic examination confirmed a metastatic breast carcinoma situated in the midline midbrain at the level of the aquaeductus sylvii. To the authors' knowledge, this is the first case report of BINO as an initial sign due to solitary metastasis of breast carcinoma.