CD8A and Granuloma: One important problem in the use of 18F-FDG PET for the diagnosis of malignancy is false positive findings due to inflammatory disease and granulomas.27–29 Additionally, in the case of the early response to immune-checkpoint inhibitors, 18F-FDG PET can be complicated by the antitumor immune response and enhanced CD8+ T-cell infiltration in and around the lesions.5 26 30 In the present study, for example, we found that three of the nine responders (PR or CR) exhibited ΔTLG of >20% between baseline and 2 weeks, and three of the nine patients with PD showed a >50% increase in TLG.