A 32-year-old woman who developed binocular horizontal diplopia was found to have an isolated fascicular sixth nerve palsy secondary to hemorrhage of a cavernous malformation within the left pontine tegmentum. There was sparing of the paramedian pontine reticular formation and absence of a horizontal gaze palsy. The natural history of cavernous malformations and a mechanism by which hemorrhage of these vascular lesions may produce minimal neurologic signs, including isolated ocular motor cranial nerve palsies, is discussed. Magnetic resonance imaging (MRI) that includes susceptibility-weighted sequences leads to their accurate diagnosis.
Department of Neurology (RMM, MLP), Massachusetts General Hospital, Boston, Massachusetts; and Department of Neurology (RMM, JPK), Brigham and Women's Hospital, Boston, Massachusetts.
Address correspondence to Misha L. Pless, MD, 15 Parkman Street, WACC Suite 835, Boston, MA 02114; E-mail: email@example.com
The authors report no conflicts of interest.