Despite the opinion that most of the changes seen were likely to represent pseudoprogression the patient has substantial symptoms from mass effect not improved with steroids. The decision was made to perform a repeat biopsy/resection of the enhancing component. 

Histology

MICROSCOPIC DESCRIPTION:

Sections show predominantly necrotic tissue with dystrophic calcification. Fragments of viable tumor are present demonstrating moderate nuclear and cellular pleomorphism. No mitoses or microvascular proliferation are identified. Immunohistochemistry results show tumor cells stain: GFAP: Positive IDH-l R132H: Negative (not mutated) ATRX: Positive (not mutated) p53: Negative Topoisomerase labeling index: Approximately 10%.

FINAL DIAGNOSIS: Predominantly necrotic, residual/recurrent Glioblastoma, IDH-l wild-type (WHO Grade IV).

Discussion

As is usually the case, histology demonstrated a combination of treatment effect and tumor. The issue is not whether or not there is any tumor present, but rather which process dominates. In this instance, the imaging findings and histology are consistent with pseudoprogression being the dominant process. The patient is thus being kept on maintenance Temazolamide and edema and enhancement are abating.