title: Long-term follow-up of vanishing tumors in the brain: how should a lesion mimicking primary CNS lymphoma be managed?
abstract: OBJECTIVE
  The spontaneous disappearance of a tumor is referred to as a vanishing tumor. Most vanishing tumors in the brain are eventually diagnosed as malignant tumors or multiple sclerosis. However, their long-term clinical course remains unclear. This study aims to elucidate the management of vanishing tumors in the brain.
  
  
  METHODS
  We defined a vanishing tumor as a case in which the tumor spontaneously disappeared or decreased to less than 70% of the initial tumor volume before definitive diagnosis and treatment (other than steroid treatment). Ten cases of vanishing tumors are reviewed.
  
  
  RESULTS
  Nine patients underwent biopsy at least once. Five patients, all of whom had malignant tumors (primary central nervous system lymphoma: 4, germinoma: 1) that recurred in 4-45 months (median: 7 months), underwent a second biopsy after the reappearance of the tumors. Five patients (tumefactive demyelinating lesion: 1, undiagnosed: 4) who had no relapse are alive, and their median follow-up time is 44 months. No cases have yet been reported of malignant brain tumors that recurred more than 5 years after spontaneous regression.
  
  
  CONCLUSIONS
  Patients with vanishing tumors should be followed up carefully by magnetic resonance imaging for at least 5 years, even after the disappearance of an enhancing lesion.
authors.affiliation: Department of Neurosurgery and Neuro-Oncology, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Okita
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Narita
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Miyakita
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohno
authors.forename: Shintaro
authors.initials: S
authors.lastname: Fukushima
authors.forename: Akiko
authors.initials: A
authors.lastname: Maeshima
authors.forename: Takamasa
authors.initials: T
authors.lastname: Kayama
authors.forename: Soichiro
authors.initials: S
authors.lastname: Shibui
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D016543:Central Nervous System Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D003711:Demyelinating Diseases / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007249:Inflammation / Q000473:pathology; D008223:Lymphoma / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D009365:Neoplasm Regression, Spontaneous / Q000473:pathology*; D013256:Steroids / Q000627:therapeutic use
chemical_list: D013256:Steroids