title: Reversible impairment of auditory callosal pathway in 5-fluorouracil-induced leukoencephalopathy: parallel changes in function and imaging.
abstract: OBJECTIVE
  To report the course of functional and imaging recovery of the auditory callosal pathway in a patient with 5-fluorouracil-induced leukoencephalopathy.
  
  
  METHODS
  Case study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  A 58-year-old man with hypopharyngeal cancer who developed 5-fluorouracil-induced leukoencephalopathy.
  
  
  METHODS
  Imaging (magnetic resonance imaging) and functional (dichotic listening test) evaluation on the auditory callosal pathway.
  
  
  RESULTS
  The patient underwent systemic chemotherapy with pirarubicin, cisplatin, and 5-fluorouracil. On the last day of the regimen, the patient suddenly became restless and convulsive. On diffusion-weighted magnetic resonance images, the signal intensity at the splenium of the corpus callosum was very high. Fluid-attenuated inversion recovery images showed no abnormal findings at this time. Intravenous methylprednisolone sodium succinate and glycerin 10% was started immediately. On the ninth day after onset, the patient was free of neurologic symptoms. Although pure-tone audiograms and speech discrimination scores were normal, dichotic listening tests revealed significant left ear suppression, indicating severe injury of the auditory callosal pathway. On fluid-attenuated inversion recovery images, the signal intensity at the splenium was high, whereas the posterior trunk was normal. At 6 weeks after onset, dichotic listening test results returned to normal and hyperintensity at the splenium was much less marked on fluid-attenuated inversion recovery images.
  
  
  CONCLUSIONS
  By using both functional and imaging modalities, this case study demonstrated, for the first time in a reversible manner, that the auditory callosal pathway runs through the most posterior part of the corpus callosum including the splenium. Diffusion-weighted magnetic resonance imaging was considered useful for early diagnosis of 5-fluorouracil-induced leukoencephalopathy.
authors.affiliation: Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Chisato
authors.initials: C
authors.lastname: Fujimoto
authors.forename: Ken
authors.initials: K
authors.lastname: Ito
authors.forename: Shinichi
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Kazunari
authors.initials: K
authors.lastname: Nakao
authors.forename: Masashi
authors.initials: M
authors.lastname: Sugasawa
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000009:adverse effects*; D001306:Auditory Pathways / Q000187:drug effects* / Q000503:physiopathology; D003337:Corpus Callosum / Q000473:pathology / Q000503:physiopathology; D015140:Dementia, Vascular / Q000139:chemically induced* / Q000503:physiopathology / Q000628:therapy; D004007:Dichotic Listening Tests; D038524:Diffusion Magnetic Resonance Imaging; D004292:Dominance, Cerebral; D005472:Fluorouracil / Q000009:adverse effects*; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D013997:Time Factors
chemical_list: D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil