F-18 FDG uptake in breast infection and inflammation

Area of Science:

• Nuclear Medicine
• Oncology
• Radiology

Background:

• Whole-body fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET) scanning is a valuable tool in breast cancer management.
• However, F-18 FDG uptake can also be associated with benign breast conditions, potentially leading to misdiagnosis.

Observation:

• This report details four cases where F-18 FDG uptake in the breast mimicked malignant disease.
• Two cases involved infectious mastitis (tuberculous and Staphylococcus aureus), presenting as intense focal uptake mimicking breast cancer on initial scans.
• Two other cases showed ring-like uptake with superimposed focal uptake after lumpectomy, initially suggesting malignancy but later found to be postsurgical hemorrhagic inflammation.

Findings:

• Histologic examination confirmed tuberculous mastitis in one patient and acute lactational inflammation with Staphylococcus aureus in another.
• The other two patients had postsurgical hemorrhagic inflammation secondary to hematomas, with no evidence of malignancy.
• These findings underscore that infectious and inflammatory mastitis can present with F-18 FDG uptake patterns similar to breast cancer.

Implications:

• Clinicians should consider infectious mastitis and postsurgical inflammatory changes in the differential diagnosis for patients with breast masses exhibiting F-18 FDG uptake.
• Careful correlation with clinical history, including tenderness or prior surgery, and appropriate follow-up investigations are crucial for accurate diagnosis.
• This highlights the importance of integrated diagnostic approaches in evaluating breast abnormalities detected by F-18 FDG PET-CT.