Axial FDG-PET image at the same level as on CT shows no uptake of the nodule. Wedge resection of the nodule reveals bronchioloalveolar carcinoma.

False negative FDG-PET for lung malignancy

* Bronchioloalveolar carcinoma
* Carcinoid tumor
* Mucinous tumors

Reasons for false negativity of these tumors may be:

* Less number of cells in tumor (low cellarity relative to tumor volume)
* Better degree of differentiation (well-differentiated), not much nuclear atypia or less mitotic figures
* Lower metabolic rate
* Less peritumoral inflammation
* Small tumor size

How to Deal?
Goes by CT appearance and clinical scenario. If there is no characteristics of benignity of the nodule, at minimum - do a closed follow up with CT.

Reference:
Gilman MD, Aquino SL. State-of-the-art FDG-PET imaging of lung cancer. Semin Roentgenol 2005;40:144.