title: Intracranial growing teratoma syndrome mimicking tumor relapse: a diagnostic dilemma.
abstract: OBJECTIVE
  It is important to differentiate growing teratoma syndrome (GTS) from tumor recurrence in the setting of an enlarging residual mass present after treatment of intracranial germ cell tumors (GCTs). The aim of this study was to determine the incidence of intracranial GTS and present its clinical manifestations in detail.
  
  
  METHODS
  The authors performed a retrospective cohort study of 52 consecutive patients with newly diagnosed intracranial GCTs who presented between January 2000 and December 2006. The records were screened to identify a study cohort in which all patients had regrowing tumor mass despite normalization of tumor markers during or after treatment of GCTs.
  
  
  RESULTS
  In 6 (11.5%) of 52 patients the pathological diagnosis was GTS. The median patient age at diagnosis was 14.5 years (range 2 months-17 years), and the primary tumors included 4 mixed GCTs and 2 immature teratomas. After second-look surgery, histological testing revealed the lesions to be mature teratoma in all patients. Three of 6 patients subsequently underwent radiation therapy and 1 patient received additional chemotherapy for spinal seeding.
  
  
  CONCLUSIONS
  In enlarging residual masses after treatment of intracranial GCTs, GTS should be kept in mind in the differential diagnosis of tumor recurrence especially if there is a radiographic mismatch with serum marker test results. If technically feasible, second-look surgery may be necessary for an accurate diagnosis.
authors.affiliation: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul, Korea.
authors.forename: Doo-Sik
authors.initials: DS
authors.lastname: Kong
authors.forename: Do-Hyun
authors.initials: DH
authors.lastname: Nam
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Lee
authors.forename: Kwan
authors.initials: K
authors.lastname: Park
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyung Jin
authors.initials: HJ
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D009373:Neoplasms, Germ Cell and Embryonal / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D024162:Second-Look Surgery; D013577:Syndrome; D013724:Teratoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome