Male, 35 years old, with history of grade 3 oligodendroglioma with 1p 19q deletion, status post re-RT 4 weeks ago with concomitant temozolamide and Avastin, on clinical trial. Findings are redemonstrated compatible with a wide left parietotemporal craniotomy. A resection cavity incorporating parts of the left frontal operculum and temporal lobe is stable in size. Thickened T2 hyperintense tissue along the posteromedial cavity margin is again seen demonstrating intrinsic T1 hyperintensity and some mild superimposed enhancement. Since the prior examination, this tissue has decreased in overall bulkiness. For example, the thickest portion previously measured up to 19 mm, and the same area now measures only 12 mm. The degree of enhancement within this tissue is also reduced. The entire region surrounding the resection cavity correlates with reduced rCBV.Contiguous with the resection cavity, there appears to be an extra-axial fluid collection following CSF on all sequences which tracks superiorly and posteriorly along the left parietal lobe exerting mild mass effect on adjacent parenchyma. This is also unchanged.T2 hyperintensity extending inferiorly from the resection cavity into the left temporal lobe is unchanged. Ill-defined T2 hyperintensity along the left ventricular atrium is also unchanged. Vague T2 hyperintensity along the right atrium may be mildly progressed.No additional suspicious or new intracranial lesions are seen. A cystic lesion within the right paramedian parietal lobe was present on all prior examinations and shows no significant interval change, likely representing a developmental cyst. Ex vacuo dilatation of the left lateral ventricle is unchanged.
1. Stable size and shape of the resection cavity involving the left frontal and temporal lobes.2. Since the prior examination, thickened tissue along the posterior medial margin of the cavity has decreased in overall bulkiness along with decreasing enhancement. The entire region correlates with reduced rCBV. Given the patient's ongoing therapeutic regimen, the interval changes may reflect either true disease response or pseudo-respopnse. 