title: Increased focal hemosiderin deposition in pediatric medulloblastoma patients receiving radiotherapy at a later age.
abstract: OBJECTIVE
  Focal hemosiderin deposition (FHD) is commonly observed on brain MRI scans of patients treated for childhood medulloblastoma (MB). The authors sought to determine the clinical significance of FHD and its relationship to patient age, radiation dose, and cognitive outcomes.
  
  
  METHODS
  A single-institution retrospective study of 93 MB patients at Lucile Packard Children's Hospital at Stanford from 1998 to 2011 identified 41 patients with a negative baseline MRI scan and at least 2 posttreatment MRI scans obtained with T2* gradient recalled echo (GRE). The number and cumulative rate of FHDs detectable by GRE were compared between patients aged 6 years and younger (early age) and aged 7-21 years (late age) at the time of radiotherapy (RT) and between low-dose (1800-2340 cGy) and high-dose (2920-3960 cGy) RT.
  
  
  RESULTS
  The median age at MB diagnosis was 7.3 years (range 0.9-21.0 years), the median clinical follow-up period was 5.8 years (range 0.8-13.4 years), and the median 5-year overall survival was 81% ± 7%. Of 30 school-aged children with MB, 21 (70%) required special education, and the median IQ of 10 tested patients was 100 (range 50-118). Thirty-three patients (80%) had FHD after a median latency of 1.9 years (range 0.1-5.9 years). Ninety-four percent (436 of 466) of the lesions arose in the supratentorial region of the brain, whereas 29 (6%) resided in the brainstem or the cerebellum. No spinal lesions were observed on routine spine MRI scans using T2 fast spin echo imaging. The mean cumulative lesion rate per year was 2.23 ± 3.05, and this rate was higher in older children at the time of RT compared with younger children (3.23 vs 0.67 per year, p = 0.002) but did not differ among different RT doses (p = 0.395). A child's IQ or need for special education showed no significant correlation with the rate of lesion development or number of lesions. None of the lesions resulted in symptomatic hemorrhage that required surgical intervention.
  
  
  CONCLUSIONS
  More FHD was observed in children treated for MB at the older ages than in those treated at the younger ages. There was no significant association of the incidence of FHD with radiation dose or cognitive outcomes, and none of the lesions required surgical intervention.
authors.affiliation: Departments of Radiology.
authors.forename: Kristen W
authors.initials: KW
authors.lastname: Yeom
authors.forename: Robert M
authors.initials: RM
authors.lastname: Lober
authors.forename: Sonia
authors.initials: S
authors.lastname: Partap
authors.forename: Nicholas
authors.initials: N
authors.lastname: Telischak
authors.forename: Rachel
authors.initials: R
authors.lastname: Tsolinas
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Barnes
authors.forename: Michael S B
authors.initials: MS
authors.lastname: Edwards
mesh_terms: D000293:Adolescent; D001921:Brain / Q000378:metabolism*; D002528:Cerebellar Neoplasms / Q000378:metabolism* / Q000532:radiotherapy*; D002648:Child; D016371:Cranial Irradiation; D005260:Female; D005500:Follow-Up Studies; D006485:Hemosiderin / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007360:Intelligence; D008279:Magnetic Resonance Imaging; D008297:Male; D008527:Medulloblastoma / Q000378:metabolism* / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D006485:Hemosiderin