False-positive PET scan in a patient with lipoid pneumonia simulating lung cancer

Purpose: Lipoid pneumonia usually presents with alveolar infiltrates or as a nonresolving process. We report a case of lipoid pneumonia that presented as a solitary pulmonary nodule and had a high standard uptake value on PET scan, thereby mimicking a malignant process. This case highlights the presence of false-positive PET imaging in a patient with lipoid pneumonia and Mycobacterium chelonae infection. Materials and Methods: The patient was examined using CT scanning. The nodule was further investigated with a PET scan using F-18 FDG and the standard uptake value was determined. Results: Histopathology following removal of the nodule confirmed the diagnosis of lipoid pneumonia, and the bronchoalveolar lavage (BAL) was reported as M. chelonae, a rapidly growing mycobacterium (RGM). Conclusion: Lipoid pneumonia can present as a PET-positive lung nodule and should be considered in the differential diagnosis and workup of a solitary pulmonary nodule.