Clinical-diagnostic relevance of breast 'incidentaloma' detected during 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography: Correlation with radiological imaging and histopathology

Aim: This study aims to study the clinical-diagnostic relevance of incidental breast uptake ('incidentaloma') on 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan performed for other indications and to correlate it with radiological imaging and histopathology. Materials and Methods: We retrospectively evaluated 3675 FDG-PET scans, identifying 43 patients with breast 'incidentaloma.' Thirty of these findings were further investigated with clinical examination, mammography (MMX), UltraSound (US) and/or magnetic resonance (MR). Cases suspected for malignancy underwent US-guided macro-biopsy (USMB) or MR-guided biopsy. Correlations between FDG-PET, radiology findings, age, and histopathology were evaluated. Results: patients who performed both US and MMX were 19. Ten consequently underwent USMB, one MR-guided biopsy, the remaining 8 were not further investigated. Nine patients had a diagnosis of malignancy. Among 11 patients who performed only US and consequently, USMB 6 had a diagnosis of malignancy. Histopathology of the 22 patients with both morphological and glucometabolic alterations showed different types of benign or malignant neoplasia, with a cumulative 68.2% incidence of malignancy. Seven lesions showed a SUV max >2.5, while the remaining 15 a SUV max <2.5. There was no statistically significant correlation between SUV max and histology, therefore SUV max parameter should not be used to discriminate between benign and malignant findings. No significant correlation between patient age and tumor characterization was found. Conclusions: incidental mammary uptake during an FDG-PET scan may represent a clue suggesting to investigate PET findings. In this subset of patients, early diagnosis may lead to a change in clinical management with a favorable impact on prognosis and a significant reduction in healthcare costs.