Beyond the lung: recognizing incidental breast lesions on chest computed tomography

With the widespread use of chest computed tomography (CT) for thoracic evaluation, incidental breast findings are increasingly encountered in routine clinical practice. Although most of these findings are benign, breast cancer may occasionally be first detected on chest CT, performed for unrelated indicators, underscoring the importance of systematic breast assessment during imaging interpretation. This review provides a practical image-based overview of breast lesions on routine chest CT, with the goal of assisting thoracic radiologists and general clinicians in recognizing clinically relevant findings. We review normal breast anatomy, common anatomic variants and breast density as visualized on chest CT, followed by characteristic CT features of benign breast lesions, imaging findings suspicious for malignancy, and expected post-treatment changes related to surgery and radiation therapy. Particularly emphasis is placed on imaging features that may overlap across benign, malignant, and post-treatment conditions, including skin and trabecular changes, calcifications, enhancement patterns, and axillary lymph node abnormalities. Diagnosis challenges and common pitfalls in CT detect lesions that warrant further attention despite the modality's inherent limitations for dedicated breast imaging. By improving familiarity with the spectrum of breast findings visible on chest CT, this review aims to promote consistent and deliberate evaluation of the breast during routine CT interpretation. In the absence of prior characterization or long-term imaging stability, suspicious or indeterminate breast imaging. Increased awareness of these findings may help reduce missed diagnoses, and support timely clinical management.