Reactive lymphohistiocytosis with recurrence in the optic chiasm.

Histiocytic infiltration of the optic chiasm is rare. We report a patient with a seizure disorder on anticonvulsant therapy, who developed systemic reactive histiocytosis. Treatment with splenectomy, corticosteroids, and anticonvulsant medication change resulted in clinical remission. The patient later developed recurrent lymphohistiocytosis restricted to the optic chiasm. Extensive re-evaluation yielded no evidence for infectious or malignant etiology. Radiation therapy and withdrawal of anticonvulsant therapy resulted in clinical remission. We conclude that both phenytoin and phenobarbital may trigger a lymphohistiocytic process and that infiltration of the visual pathway is possible.