Diffuse low-grade oligodendrogliomas extend beyond MRI-defined abnormalities.
BACKGROUND
Imaging determinations of the spatial extent of diffuse low-grade gliomas (DLGGs) are of paramount importance in evaluating the risk-to-benefit ratio of surgical resection. However, it is not clear how accurately preoperative conventional MRI can delineate DLGGs.


METHODS
We report a retrospective histologic and imaging correlation study in 16 adult patients who underwent serial stereotactic biopsies for the diagnosis of untreated supratentorial well-defined and non-contrast-enhanced DLGG, in whom biopsy samples were taken within and beyond (OutBSs) MRI-defined abnormalities.


RESULTS
Thirty-seven OutBSs that extended from 10 to 26 mm beyond MRI-defined abnormalities were studied. Immunostaining revealed MIB-1-positive cells (i.e., cycling cells) in all but 2 of the OutBSs. None of the MIB-1-positive cells coexpressed glial fibrillary acidic protein, and all of them coexpressed OLIG2. MIB-1-positive cells were cycling isolated tumor cells, because 1) their morphologic characteristics reflected those of tumor cells, 2) the number of MIB-1-positive cells per square centimeter was significantly higher than that of controls, 3) the number of MIB-1-positive cells per square centimeter was positively correlated with the tumor growth fraction (p = 0.012), and 4) the number of MIB-1-positive cells per square centimeter in OutBSs decreased with distance from the tumor (p = 0.003).


CONCLUSIONS
This study demonstrates, using a multiscale correlative approach, that conventional MRI underestimates the actual spatial extent of diffuse low-grade gliomas (DLGGs), even when they are well delineated. These results suggest that an extended resection of a margin beyond MRI-defined abnormalities, whenever feasible in noneloquent brain areas, might improve the outcome of DLGGs.
Pallud
J
J
Service de Neurochirurgie, Hôpital Sainte-Anne, Paris cedex 14, France. johanpallud@hotmail.com
Varlet
P
P
Devaux
B
B
Geha
S
S
Badoual
M
M
Deroulers
C
C
Page
P
P
Dezamis
E
E
Daumas-Duport
C
C
Roux
F-X
FX
D000293:Adolescent; D000328:Adult; D000974:Antibodies, Antinuclear / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D001706:Biopsy / Q000379:methods; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D001932:Brain Neoplasms / Q000175:diagnosis*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism; D016900:Neurofilament Proteins / Q000378:metabolism; D000076104:Oligodendrocyte Transcription Factor 2; D009837:Oligodendroglioma / Q000175:diagnosis*; D011522:Protons; D012189:Retrospective Studies; D013223:Statistics as Topic; D055815:Young Adult
D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D051792:Basic Helix-Loop-Helix Proteins; D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D000076104:Oligodendrocyte Transcription Factor 2; D011522:Protons; C440408:MIB-1 antibody; C405708:OLIG2 protein, human