Abstract Details

Title Histologic Profiles and MRI Characteristics of Cerebral Radiation Necrosis Compared with Recurrent Brain Tumor Following Radiation

Topic Neuro-oncology

Presentation(s) IN10 - (-)

Poster/Presentation
Number 010

Objective

Background Distinguishing CRN from RBT is critical in patient management. Histology of lesion biopsy/resection remains the standard for diagnosis. Published reports of histologic findings in CRN are limited by lack of a) definition of the amount of residual/recurrent tumor allowed b) scoring of histological features and c) comparison to pretreatment tumor. Morphologic MRI features of CRN are described (Rogers et al 2010) but have not been applied to RBT to determine their specificity.

Design/Methods Retrospective review of histological findings in CRN (<20% tumor) versus RBT (>80% tumor) in patients undergoing biopsy/resection of imaging progression lesion and in pretreatment tumor samples (when available). A unique data set of histologic characteristics and a scoring system (minimal, small, abundant, dominant) are applied to slides reviewed by a neuropathologist (MC) blinded to diagnosis. MRIs obtained pretreatment and immediately prior to lesion resection are reviewed by 2 neuroradiologists blinded to diagnosis. Imaging characteristics are similary scored.

Results 30 cases each of CRN and RBT have been identified; primary tumor was GBM in the majority. Initial histology review indicates that inflammatory infiltrates, vascular telangectasia and fibrinoid vascular necrosis are more common in CRN, as are "RT astrocytes" and demyelination. Vessel thickening and hyalizination are equally common in both. Comparison of these histologic findings with initial tumor pathology and MRI is ongoing.

Conclusions This study provides important data on identification and grading of histological features in CRN and RBT. It is hoped that comparison of these findings with initial tumor pathology will enhance diagnostic criteria of CRN vs RBT. Asssessment with MRI findings may aid in determining distinguishing MRI features.

Authors/Disclosures
Lisa R. Rogers, DO, FAAN (Henry Ford Hospital) PRESENTER	Dr. Rogers has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Novocure .
	No disclosure on file
	No disclosure on file
	No disclosure on file
Frederick G. Freitag, DO (Medical College of Wisconsin)	No disclosure on file
	No disclosure on file
Mark Cohen	Mark Cohen has nothing to disclose.

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