A case of primary malignant lymphoma involving the splenium of the corpus callosum is reported in a 54-year-old woman presenting with symptoms of increased intracranial pressure. In view of the prominent cerebral edema associated with the intracranial lymphoma, dexamethasone was initiated at a daily dosage of 8 mg by intravenous administration. Computed tomography scans obtained 10 days after admission revealed dramatic regression of the lesion which corresponded with clinical remission. Steroid-induced regression of primary malignant lymphoma of the brain as evidenced by computed tomography is reviewed in the literature, and the role of corticosteroids is discussed.