A case of subacute leukoencephalopathy in a 2 year-old boy with acute lymphoblastic leukemia was reported. Because of CNS leukemia, he received a course of intrathecal methotrexate, cytosine arabinoside, and hydrocortisone in addition to 2,650 rads of whole skull radiation. Three months after the onset of CNS leukemia, he developed slurred speech and staggering gait, and his condition was slowly deteriorated. He showed drowsiness, irritability, neck stiffness, involuntary movement of neck, opsoclonus, nystagmus, and left facial palsy. The blast cells were cleared from CSF, but the protein concentration was persistently elevated. EEG showed diffuse slowing of background activity. With the development of spasticity and decerebrated rigidity, he died 3 months later.
The neuropathological examination revealed multifocal necrosis in the cerebral white matter, demyelination, striking axonal damage with swelling and calcification, and thrombosis and fibrinoid necrosis of the blood vessel walls. Intrathecal methotrexate, whole skull radiation, and CNS leukemia may be causally related to the development of this disease. We reviewed in the literatures 26 cases of subacute leukoencephalopathy.