This patient presented with sudden onset, painful, horizontal, binocular diplopia. He has findings of a relatively comitant, large angle esotropia with significant abduction deficits in both eyes. He had no other neurologic deficits or signs/symptoms of raised intracranial pressure. His findings are consistent with bilateral cranial nerve VI palsies. MRI shows a large, heterogeneous mass with mass effect on the brainstem in the prepontine and premedullary cistern that was thought to represent an organized retroclival hematoma. His pathology was thought to be secondary to compression (by this mass at the clivus) of both sixth nerves as they enter Dorello's canal near each other.
Cranial nerve VI (abducens nerve) innervates the lateral rectus muscle that is responsible for abduction of the eye. Weakness of the lateral rectus will result in binocular, horizontal diplopia and patients will demonstrate an abduction deficit and an esotropia.
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