Localization of F-18 FDG in Nocardia lung infection

F-18 FDG is the most commonly used radiotracer for PET. PET has become a very powerful tool for evaluating malignancy. However, localization of FDG is not specific for malignancy, and a number of benign conditions may accumulate FDG. The authors recently encountered a case of pulmonary nocardiosis exhibiting increased uptake of FDG on a PET scan performed to exclude pulmonary malignancy. Markedly increased FDG uptake led to a biopsy that demonstrated Nocardia infection. Localization of FDG in nocardiosis may be regarded as a false-positive case when imaging for malignancy, but can uncover a lethal condition that may otherwise go unnoticed.