PET-CT scan has demonstrated to be very effective in lung cancer diagnosis and staging, but lung cancer has multiple ways of presentation, which can lead to an error in diagnosis imaging and a delay on the beginning of specific treatment. We present a case of a 77-year-old man with an initial PET-CT scan showing high 18F-FDG intake, suggesting a bilateral pneumonia, who was finally diagnosed of an EGFR-mutant lung adenocarcinoma. EGFR-activating mutation allowed us to start treatment with the oral tyrosin kinase inhibitor Gefitinib, obtaining a rapid and sustained response. Histological confirmation of imaging findings is always necessary to avoid diagnostic errors.
Staging of nonsmall-cell lung cancer was one of the first approved indications for the use of positron emission tomography (PET) [
We present a 77-year-old man, with no history of smoking, admitted to the emergency room with a 2 month history of malaise, shortness of breath, and weight loss. His medical history involved controlled heart failure, arterial hypertension, hypercholesterolemia, and obstructive sleep apnea syndrome. Blood count, liver, and renal functions were normal. Chest X-ray showed areas of consolidation in both lung bases, predominantly left.
A CT-scan of the chest demonstrated diffuse bilateral ground glass nodules, ill-defined areas of pulmonary opacities with “crazy-paving” pattern in right lower and middle lobes, and extensive air-space consolidation in left lung (Figures
CT-scan of the chest shows bilateral nonsolid pulmonary nodules (a and b:
The PET-CT scan (low-dose CT) reported an extensive and heterogeneous deposit of
PET-CT scan shows extensive and heterogeneous 18F-FDG uptake in both lungs in correlation with bilateral ground glass images and bilateral ill-defined pulmonary opacities on CT image (coronal planes (a, b, and c), volumetric projection (d), and axial planes (e, f, and g)). Hypermetabolic lymph nodes are observed in right supraclavicular, left mediastinal, and subcarinal regions (volumetric projection (d)) as well as subcarinal hypermetabolic nodes (axial planes (e and g)).
Bronchoscopy demonstrated serous secretions predominantly in the left bronchial tree. Bronchial aspirate, bronchoalveolar lavage, and bronchial biopsy resulted positive for adenocarcinoma. All bacteriological tests performed were negative.
In this case an activating mutation on exon 19 of epidermal growth factor receptor (
Lung cancer has multiple ways of presentation, which can lead to an error in diagnostic imaging, therefore histological confirmation is always necessary. Because EGFR-mutant tumours show lower 18F-FDG uptake in PET-CT scan [
In this case, with initial imaging/metabolic procedures suggesting bilateral inflammatory or infectious process, delay of histological confirmation would have had a negative impact in patient’s survival and quality of life.
None of the authors have any conflict of interests to declare.