18F-Labeled WBC PET/CT Scan in a Case of Recurrent Glioblastoma Multiforme, Presented as Pyrexia of Unknown Origin.

Neoplastic causes account for approximately 10% to 20% cases of PUO (pyrexia of unknown origin). The mechanisms by which malignancies induce fever are not fully understood. The release of pyrogenic cytokines either directly from tumor cells or from macrophages responding to tumor are likely to play a major role, which acts on the hypothalamus, causing a change in the thermostatic set point.