Patients with multiple sclerosis may present clinical data suggestive of cerebral tumor. It has been accepted that multiple sclerosis failed to show expansive signs in the computerized tomography (CT). However, since 1979 a total number of 13 patients have been reported to have expansive images at the CT. We report 3 cases with clinical symptoms suggesting a cerebral tumor associated with expansive signs at the CT. The subsequent follow-up of these patients confirmed the diagnosis of clinically defined multiple sclerosis. The management of these patients is difficult. Those patients with previous history suggestive of multiple sclerosis should be probably treated with steroids and followed with serial CT. If a clear recovery was not achieved in a relatively short term, a cerebral biopsy is recommended to rule out a neoplasm. When the clinical presentation begins with signs suggestive of a neoplasm, the cerebral biopsy is recommended.