We report a case in which 18F-FDG PET was able to discriminate pseudoprogression from progression observed on contrast-enhanced (CE) MRI (CE-MRI). A 56-year-old male patient with anaplastic oligodendroglioma demonstrated markedly increased tumor enhancement on CE-MRI 1 month after completing radiation therapy (RT), suggesting radiological progression. However, the patient was clinically improved and therefore received an early-therapy response assessment PET to assess for pseudoprogression. PET showed low tumor uptake indicating stable disease. Follow-up CE-MRI at 3 and 4 months post-RT confirmed stable disease. This case emphasizes the value of 18F-FDG PET when pseudoprogression is clinically suspected.
From the *Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania; and †Department of Neurology and Department of Medicine, Division of Hematology/Oncology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
Received for publication August 10, 2012; and revision accepted January 4, 2013.
Institution where work was performed: Department of Radiology, University of Pittsburgh, Pittsburgh, PA.
Conflicts of interest and sources of funding: This work was supported by the US National Institutes of Health research grant U01 CA140230 and UPCI shared resources award P30CA047904.
Reprints: James M. Mountz, MD, PhD, Department of Radiology, Division of Nuclear Medicine, University of Pittsburgh Medical Center, 200 Lothrop Street, Pittsburgh, PA 15213. E-mail: firstname.lastname@example.org.