1. Lung nodules are frequently encountered entities. FDG-PET has become the mainstay in non-invasive evaluation for suspected malignancy. If intensely avid, it is considered malignant until proven otherwise. However, substantial literature exists on malignant but non-avid nodules.
2. Variety of neoplastic and non-neoplastic etiologies can manifest as a non-avid nodule. We idenitifed malignant causes including adenocarcinoma, squamous cell carcinoma, well/poorly differentiated neuroendocrine tumour. Although it may be tempting to consider FDG-PET in a simple dichotomous manner, one must review temporal and radiological characteristics.
3. By being familiar with common neoplastic and non-neoplastic etiologies, and some characteristic non-PET features, the reader can be more confident in recommending either surveillance or invasive intervention.
FDG-PET principles and definition of a non-avid pulmonary nodule.
Review of literature on neoplastic non-avid nodules and discussion on possible mechanisms for lack of FDG uptake
Review of pathologically proven neoplastic and non-neoplastic cases, with discussion of helpful radiological features
Summary of key points.
Jin, S,
Nandurkar, D,
"Not so sweet": The FDG Negative Pulmonary Nodule Spectrum of Disease—Review of Radiological/histological Findings of 30 Non-avid Pulmonary Nodules with Neoplastic and Benign Etiologies. Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL.
http://archive.rsna.org/2014/14003818.html
