Downgaze palsy and bilateral ptosis due to a thalamomesencephalic lesion.

An unusual combination of downgaze palsy and bilateral ptosis occurred in a patient with central nervous system lymphoma involving bilateral thalamus and midbrain tegmentum. Following treatment with corticosteroids, the transition from total paralysis of downgaze to the supranuclear form was noted, along with alleviation of ptosis, followed by complete resolution of both. The results of serial magnetic resonance images were consistent with our interpretation that his initial eye signs were caused by the combined involvement of the bilateral rostral interstitial nucleus of the medial longitudinal fasciculus (supranuclear downgaze palsy) and the oculomotor subnuclei (nuclear palsy of the inferior recti and levator palpebrae muscles).