Glioblastoma with coagulative necrosis due to bevacizumab

An ill-defined mass involving the medial and superior aspect of the right frontal lobe with mild mass effect is present. Minor patchy enhancement is present posteriorly correlating with reduced ADC values. 

Features are those of a diffuse adult glioma, most likely grade 3 or 4. 

Resection cavity with possible minor residual tumor posteriorly within the supplementary motor area. 

Previous bifrontal craniotomy and underlying resection cavity in the right frontal lobe with associated post-surgical change. Nodular contrast enhancement at the posterior inferior edge of the resection cavity has markedly increased in size over the last two studies (not shown).

There are also new foci of enhancement in the genu and body of the right corpus callosum. Some of the enhancing components demonstrate low ADC values and are associated with elevated CBV. Spectroscopy demonstrates decreased NAA, elevated choline and a lactate peak.

Conclusion: Increase in size of the enhancing tumor and surrounding high FLAIR signal. Two new enhancing nodules in the corpus callosum. Low ADC and elevation of rCBV in the new enhancing components suggest disease progression rather than treatment effect.

The patient has been on bevacizumab for 5 months. Adjacent to the frontal horn of the lateral ventricle is an area of diffusion restriction with profoundly depressed ADC values. This is consistent with an area of coagulative necrosis secondary to bevacizumab.