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

Clin Nucl Med. 2004 Jul;29(7):426-8. doi: 10.1097/01.rlu.0000129123.61966.e0.

Abstract

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.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Aged, 80 and over
  • Bronchoalveolar Lavage Fluid / microbiology
  • Diagnosis, Differential
  • False Positive Reactions
  • Fluorodeoxyglucose F18
  • Humans
  • Lung Neoplasms / diagnostic imaging*
  • Male
  • Mycobacterium Infections, Nontuberculous / diagnostic imaging
  • Mycobacterium chelonae / isolation & purification
  • Pneumonia, Lipid / diagnostic imaging*
  • Radiopharmaceuticals
  • Solitary Pulmonary Nodule / diagnostic imaging
  • Tomography, Emission-Computed*

Substances

  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18