Incidental breast lesions identified by 18F-fluorodeoxyglucose-positron emission tomography

Positron emission tomography (PET) scanning is now part of the standard evaluation for patients with a variety of different malignancies. We describe our experience with breast incidentalomas in a large series of PET scans performed for patients without a known history of breast cancer.

From March 2000 through June 2007, approximately 45,000 PET scans were performed; 163 had breast findings unrelated to the primary malignancy. In 103 of 163 (63%), findings included physiologic variation, lactation, implants, or benign calcifications. Chart review was conducted in the remaining 60 of 163 patients (37%).

In 20 of 60 patients (33%), no additional evaluation was performed due to advanced stage of the primary malignancy; 40 of 60 (67%) underwent additional imaging and evaluation. In 16 of 40 patients (40%), the lesion resolved on repeat PET; the lesion persisted in 10 of 40 (25%). Additional breast imaging was performed in 14 of 40 (35%). In total, 12 of 40 (30%) underwent biopsy; 7 of 40 (18%) were positive for malignancy.

In our experience, 29% of breast incidentalomas (7 of 24) with persistent imaging findings were malignant. Further evaluation of these lesions should be based on overall clinical status. In patients where results would not change overall management, biopsy may not be warranted.