PMC7373832_01
Initial CT thorax demonstrated no acute pulmonary infiltrates or lymphadenopathy (a). A morphologically normal ATS station 2R lymph node is highlighted by the white arrow (b)
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Fig1
The CT at baseline demonstrated no acute pulmonary parenchymal abnormality or lymphadenopathy (Fig. 1); however, an incidental 3.4 cm right middle lobe mass was noted (Fig. 2; Image A) and a PET/CT was requested for further characterisation. 
Initial CT thorax detected a right middle lobe mass (a). Subsequent PET-CT demonstrated no FDG uptake b (CT) and c (fused PET-CT)
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Fig2
The CT at baseline demonstrated no acute pulmonary parenchymal abnormality or lymphadenopathy (Fig. 1); however, an incidental 3.4 cm right middle lobe mass was noted (Fig. 2; Image A) and a PET/CT was requested for further characterisation.  PET/CT investigation, the patient became progressively unwell with the development of a febrile illness and increased oxygen requirement secondary to type I respiratory failure. PET/CT (GE Discovery VCT; USA), performed 9 days following the initial CT thorax, demonstrated no FDG uptake in the right middle lobe mass, likely a benign entity (Fig. 2b, c).
a PET maximum intensity projection (MIP), b-d: axial attenuation corrected PET, axial CT lung windows and axial fused PET/CT images through the lower thorax. e PET maximum intensity projection (MIP), f-h: axial attenuation corrected PET, axial CT mediastinal windows and axial fused PET/CT images through the superior mediastinum. These images highlight intense bilateral parenchymal metabolic activity, more prominently in the right lower lobe (images a-d) and high uptake in an ATS station 2R lymph node (e-h). Please note spurious right ureteric activity on the MIP images (images a and e)
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Fig3
There were however other unexpected findings which included intensely FDG positive, predominantly mid- to lower zone, diffuse bilateral subpleural intra- and interlobular septal thickening and ground-glass opacification, with patchy areas of a higher intensity of FDG uptake in the bases associated with consolidation (Fig. 3a-d). Thoracic Society (ATS) station level 2R mediastinal lymph node with SUVmax of 8.7 (Fig. 3e-h). There was no other FDG-positive abnormality outside the thorax. 