Schwannoma is a rare intramedullary tumor. There has been no reported case about interval aggravation on follow-up MR imaging. We report initial and follow-up MR findings of a thoracic intramedullary schwannoma with syringomyelia and edema in a patient without neurofibromatosis. Intramedullary schwannoma should be included for differential diagnosis of intramedullary tumor even though followup MR imaging shows interval increase in size of the tumor and extent of associated edema to mimic malignancy.