title: Radiographic occult cerebellar germinoma presenting with progressive ataxia and cranial nerve palsy.
abstract: BACKGROUND
  Although the usefulness of susceptibility-weighted imaging (SWI) for detecting basal ganglia germinoma has been reported, the technique is not widely used. We recently encountered an unusual case of primary cerebellar germinoma, presenting with progressive ataxia and cranial nerve palsy, characterized by gradually enlarging low-intensity lesions visible with both T2*-weighted imaging (T2*WI), which were the key to the diagnosis.
  
  
  METHODS
  A 30-year-old man was referred to our hospital because of slowly progressive dizziness and mild ataxia. Magnetic resonance imaging (MRI) revealed a small, low-intensity spot in the left cerebellar peduncle on the T2*WI and SWI without enhancement. Cerebral angiography revealed no vascular abnormality. The serum α-fetoprotein value was normal. A steroid-pulse was administered as a therapeutic and diagnostic trial, but the symptoms improved little. The patient was discharged from the hospital but soon developed brainstem dysfunction, characterized by dyspnea or hiccups, and he was readmitted. T2*WI imaging revealed expanded and extended spotty lesions in the cerebellum and brainstem, which had not enhanced with contrast agent previously. Targeted stereotactic biopsy of the newly enhanced cerebellar lesion was performed; histopathological examination of the tissue revealed pure germinoma. Serum and cerebral spinal fluid values of beta-human chorionic gonadotropin were not significantly elevated. Chemotherapy with carboplatin and etoposide was initiated. The enhanced lesion disappeared promptly, but the patient continued to require assisted automatic ventilation because of paralysis of respiratory muscles.
  
  
  CONCLUSIONS
  We conclude that enlarging low-intensity lesions on T2*WI and SWI may be a reliable clue to the diagnosis of germinomas, irrespective of their location, even without enhancement. Biopsy of the tumor at an early stage is the only way to make the diagnosis conclusively and enable prompt start of treatment.
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Minami
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Hidehito
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Department of Pathology for Regional Communication, Kobe University Hospital, Kobe, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Hirose
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Mori
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Maeyama
authors.affiliation: Department of Neurology, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sekiya
authors.affiliation: Department of Neurology, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uenaka
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakamizo
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nagashima
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Katsu
authors.initials: K
authors.lastname: Mizukawa
authors.affiliation: Department of Diagnostic Pathology, Kobe University Hospital, Kobe, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Itoh
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan. takasasa@med.kobe-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasayama
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Kusunoki-cho 7-5-2, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Kohmura
mesh_terms: D000328:Adult; D001259:Ataxia / Q000175:diagnosis* / Q000209:etiology; D002528:Cerebellar Neoplasms / Q000150:complications / Q000175:diagnosis*; D003389:Cranial Nerve Diseases / Q000175:diagnosis* / Q000209:etiology; D018237:Germinoma / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male