Bilateral trochlear palsy due to a primary brain tumor

Abstract

Bilateral trochlear palsy is an uncommon ocular motor disorder commonly caused by closed head trauma and rarely by tumors. A 40-year-old man is presented with a bilateral trochlear palsy caused by tumor infiltration of a pilocytic astrocytoma extending from the dorsal midbrain with infiltration of the anterior medullary velum to the fourth ventricle. In the absence of head trauma, bilateral trochlear palsy is a good localizing sign for the dorsal midbrain region and makes brain imaging necessary.