Question 508
{"accessible":false,"alternatives":[{"id":2546,"text":"post-operative enhancement"},{"id":2547,"text":"pseudoprogression"},{"id":2548,"text":"pseudoresponse"},{"id":2549,"text":"radiation induced meningioma"},{"id":2550,"text":"tumor progression"}],"archived":false,"correctAlternativeId":2547,"explanation":"\u003cp\u003eThis is a typical description and timing for pseudoprogression, typically seen between 0 and 6 months after completion of radiotherapy, particularly in MGMT methylated tumors.\u0026nbsp;\u003c/p\u003e\u003cp\u003eAlthough tumor progression is a possibility, one would expect increased CBV and tumor MRS trace (particularly elevated choline).\u0026nbsp;\u003c/p\u003e\u003cp\u003eRadiation-induced meningiomas occur many years after treatment. Post-operative enhancement should be minimal or absent by ~5 months.\u0026nbsp;\u003c/p\u003e\u003cp\u003ePseudoresponse is seen when there is an\u0026nbsp;apparent improvement due to therapy, usually in the setting of anti-angioneogenesis drugs (e.g. Avastin).\u0026nbsp;\u003c/p\u003e","id":508,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/508","nextQuestionPath":null,"relatedArticles":[{"id":4910,"title":"Glioblastoma, IDH-wildtype","link":"/articles/glioblastoma-idh-wildtype?lang=us"},{"id":32837,"title":"Methylguanine-DNA methyltransferase (MGMT)","link":"/articles/methylguanine-dna-methyltransferase-mgmt?lang=us"},{"id":34958,"title":"Tumor pseudoresponse","link":"/articles/tumour-pseudoresponse?lang=us"},{"id":34959,"title":"Tumor pseudoprogression (brain tumors)","link":"/articles/tumour-pseudoprogression-brain-tumors?lang=us"}],"alsoUsedIn":[{"id":1169,"kind":"Course","title":"Adult Neuroradiology Review Course - page 1169","link":"https://radiopaedia.org/courses/adult-neuroradiology-review-course/pages/1169"},{"id":1169,"kind":"Course","title":"Adult Neuroradiology Review Course - page 1169","link":"https://radiopaedia.org/courses/adult-brain-mri-review-course-2015-online-video/pages/1169"}],"stem":"\u003cp\u003eA 65-year-old female with a proven glioblastoma (IDH-1 wild-type, MGMT methylated) undergoes Stupp protocol combined chemoradiotherapy. Two months after completion of radiotherapy, a follow-up MRI demonstrate a\u0026nbsp;substantial increase in size of a peripheral enhancing component with abundant surrounding vasogenic edema resulting in mass effect. The enhancing component\u0026nbsp;has low cerebral blood volume and spectroscopy demonstrates a dominant lipid and lactate peak, with minimal choline or NAA.\u0026nbsp;\u003c/p\u003e\u003cp\u003eWhat 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/508"}],"attemptsPercentages":[{"alternativeId":"2547","percentage":90},{"alternativeId":"2546","percentage":3},{"alternativeId":"2550","percentage":3},{"alternativeId":"2548","percentage":2},{"alternativeId":"2549","percentage":2}],"promptToLogin":false,"questionManager":false,"articleId":"radiation-induced-meningiomas"}