One-and-a-half syndrome in a patient with metastatic breast disease.

This report reviews the clinical course of a patient with breast carcinoma presenting with the classic one-and-a-half syndrome. She had no saccades to the left and no leftward eye deviation on oculocephalic movement. Her clinical examination suggested involvement in the medial longitudinal fasciculus, paramedian pontine reticular formation, and abducens nucleus. There has only been one previous case reported of a metastasis producing this syndrome. A computed tomography scan confirmed the pontine location of the lesion.