Optic nerve involvement in acute lymphoblastic leukemia.

Leukemic infiltration of the optic nerve is rare. We describe the diagnostic assessment and the outcome in two adult patients suffering from acute lymphoblastic leukemia with T phenotype. In both cases the leukemic involvement of the eye was observed as an isolated extramedullary relapse followed after several months by hematological relapse. CT and MRI scans were negative, while an A-scan echography of the eye clarified the diagnosis. Early radiotherapy caused recovery of visual acuity in one case. A-scan echography is the most sensitive investigation for the early recognition of ocular localization in acute leukemias.