Acute disseminated encephalomyelitis(ADEM) is an uncommon immune-mediated inflammatory demyelinating disorder that typically affects the white matter of the central nervous system. Radiologic findings of acute disseminated encephalomyelitis are not pathognomomic. The differential diagnosis is always difficult. Occasionally, the clinical features, radiological and histopathological findings of patients with acute disseminated encephalomyelitis mimic the brain tumor or other space occupying lesions. The authors report a 6-year-old girl who presented with right hemiparesis two days after nausea and vomiting. Brain MRI of the patient revealed non-enhanced multiple cystic lesions in subcortical white matter of both cerebral hemisphere with prominent edema. One of the cystic lesions was resected to differentiate with metastatic tumor or inflammatory disease such as abscess and confirmed as the acute disseminated encephalomyelitis via various immunohistochemical stains. Pertinent literature is reviewed with discussion on this uncommon ADEM associated with multiple cystic lesions.