Multimodal Approach to a Photopenic Defect on FDOPA PET/MR in a Case of Glioblastoma and its Progression

We report the case of a 52-year-old man who presented with a diffuse, nonenhancig right frontotemporal lesion on MRI, without a solid component. Neither FDG nor FDOPA PET/MR was able to identify a hypermetabolic focus to guide the biopsy, but photopenic defect. Stereotactic biopsy performed at the temporal region revealed a IDH wild-type glioblastoma with a Ki-67 index below 1%. Seven months after biopsy, aggressive tumor growth was observed around the biopsy tract, with a solid enhancing mass and very high FDOPA and FDG uptake, typical for a glioblastoma. The patient died 28 months after diagnosis.