FDG/PET uptake in asymptomatic multilobar Chlamydia pneumoniae pneumonia

Area of Science:

• Oncology
• Infectious Diseases
• Radiology

Background:

• Fluorodeoxyglucose-positron emission tomography (FDG-PET) is crucial for cancer staging.
• False-positive FDG uptake is known in inflammatory and infectious respiratory conditions.
• No prior reports linked Chlamydia pneumoniae infection to FDG uptake.

Observation:

• An incidental diagnosis of asymptomatic Chlamydia pneumoniae pneumonia was made during thyroid cancer screening.
• Three pulmonary consolidation areas showed strong FDG-PET/CT uptake, resembling malignancy.
• Radiological findings and positive IgM antibodies confirmed Chlamydia pneumoniae infection.

Findings:

• Chlamydia pneumoniae respiratory infection presented as FDG-PET-avid lesions.
• The infection mimicked pulmonary malignancy on PET/CT imaging.
• Antibiotic treatment led to complete resolution of the observed pulmonary consolidations.

Implications:

• Positive FDG-PET findings require careful interpretation, as they are not exclusively indicative of malignancy.
• Chlamydia pneumoniae infections should be considered in the differential diagnosis of FDG-avid pulmonary lesions.
• This case expands the understanding of FDG-PET limitations in oncological imaging.