Question 2105
{"accessible":false,"alternatives":[{"id":10449,"text":"AT-RT"},{"id":10450,"text":"ependymoma"},{"id":10451,"text":"medulloblastoma"},{"id":10452,"text":"pilocytic astrocytoma"},{"id":10453,"text":"pineoblastoma"}],"archived":false,"correctAlternativeId":10451,"explanation":"\u003cp\u003eMedulloblastoma makes up 40% of all posterior fossa tumors. It is an embryonal tumor and is a highly cellular tumor that results in low ADC values in its solid components.\u003c/p\u003e\u003cp\u003eEpendymomas may have elements that have low ADC values, but they are much less common and ependymomas only represent 15% of posterior fossa tumors.\u003c/p\u003e\u003cp\u003eAT-RTs are also embryonal tumors that classically have low ADC values, but they are much less common and would really only be considered in much younger children (e.g. infants under 18 months).\u003c/p\u003e","id":2105,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2141","nextQuestionPath":null,"relatedArticles":[{"id":5335,"title":"Medulloblastoma","link":"/articles/medulloblastoma?lang=us"}],"alsoUsedIn":[{"id":992,"kind":"Course","title":"2021 Virtual Conference Private Use - page 992","link":"https://radiopaedia.org/courses/2021-virtual-conference-private-use/pages/992"},{"id":992,"kind":"Course","title":"Radiopaedia 2021 - isoCME - page 992","link":"https://radiopaedia.org/courses/radiopaedia-2021-isocme/pages/992"},{"id":992,"kind":"Course","title":"2022 Virtual Conference Private Use - page 992","link":"https://radiopaedia.org/courses/2022-virtual-conference-private-use/pages/992"},{"id":970,"kind":"RestrictedPage","title":"Page 970 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/970"},{"id":955,"kind":"RestrictedPage","title":"Page 955 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/955"},{"id":1,"kind":"LiveSchedule","title":"1","link":"https://radiopaedia.org/admin/live_schedules/1"},{"id":53,"kind":"LiveSchedule","title":"53","link":"https://radiopaedia.org/admin/live_schedules/53"},{"id":945,"kind":"Course","title":"Radiopaedia 2021 - isoCME - page 945","link":"https://radiopaedia.org/courses/radiopaedia-2021-isocme/pages/945"},{"id":945,"kind":"Course","title":"2021 Virtual Conference Private Use - page 945","link":"https://radiopaedia.org/courses/2021-virtual-conference-private-use/pages/945"},{"id":945,"kind":"Course","title":"Paediatric Lectures - page 945","link":"https://radiopaedia.org/courses/paediatric-lectures/pages/945"}],"stem":"\u003cp\u003eA 7-year-old child presents with a worsening headache, waking him from sleep. An MRI is performed which shows a\u0026nbsp;posterior fossa tumor and secondary obstructive hydrocephalus. The solid component of the tumor has low ADC values. What is the most likely diagnosis?\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/2105"}],"attemptsPercentages":[{"alternativeId":"10453","percentage":1},{"alternativeId":"10452","percentage":6},{"alternativeId":"10451","percentage":88},{"alternativeId":"10449","percentage":2},{"alternativeId":"10450","percentage":3}],"promptToLogin":false,"questionManager":false,"articleId":"atypical-teratoidrhabdoid-tumor"}