Objective      To determine the diagnostic value of

18

F-FDG PET/CT in pulmonary atypical manifestation in order to improve the diagnostic accuracy for such type of diseases.       Methods      A retrospective analysis was conducted on 13 cases with pulmonary lesions who received

18

F-FDG PET/CT from Jan 2009 to Jun 2011 in our department

but were gi

ven wrong diagnosis. These lesions included 4 malignant tumors (3 bronchiolovalveolar carcinomas and 1 papillary adenoma)

and 9 benign lesions (2 inflammatory pseudotumors and 7 tuberculomas) according the results of needle biopsy or post-operation pathology.       Results      In 4 malignancies

18

F-FDG PET/CT presented solitary pulmonary nodules in 3 cases (2 lesions were with smooth margin and 1 with slight lobulation in the edge

and there were 2 cases had pleural adhesion)

and patchy higher density shadow in 1 case. SUV

max

ranged from 1.9 to 4.2

while that of the patchy shadow was only 1.9. Nodule diameter was from 1.5 to 2.4 cm

with an average of 2.0 cm.

18

F-FDG PET/CT misdiagnosed these 4 malignant tumors as 2 inflammatory pseudotumors

1 tuberculoma and 1 focal inflammation. All benign cases were solitary pulmonary nodules displayed by

18

F-FDG PET/CT

of which 3 with smooth margin

3 pleural adhesion

4 slight lobulation in the edge and 2 calcification in lesion. Their SUV

max

was 2.8 to 5.1 and nodule diameter was 1.8 to 3.2 cm with 2.4 cm in average. These were all misdiagnosed as peripheral lung cancer by

18

F-FDG PET/CT.       Conclusion      In

18

F-FDG PET/CT whole body imaging

pulmonary atypical manifestations lack conventional features for differential diagnosis. Clinical data and other auxiliary examinations should be carefully considered to avoid errors in diagnosis.