Diffuse Metabolic Activation of Reticuloendothelium on F-18 FDG PET Imaging in a Case of Visceral Leishmania

Fever of unknown origin may represent a substantial diagnostic challenge. Metabolic total body imaging may be of help in detecting inflammatory foci when clinical evaluation cannot identify the source of prominent local symptoms. In particular, F-18 FDG PET may offer superior sensibility in detecting the considerable local increase of metabolism of activated granulocytes and macrophages in focal inflammation. On the other hand, systemic pathology with diffuse macrophage activation may determine peculiar PET patterns, contributing to draw the clinicianʼs attention to diffuse rather than focal illness. A case of PET/CT total body imaging in visceral Mediterranean leishmaniasis, showing a diffuse increase of reticuloendothelial metabolic activity, is presented here.