Beyond the Primary Complaint: Analysis of Missed and Incidentally Detected Breast Cancers on Emergency Chest CT Scans

To investigate the frequency of breast malignancies missed or incidentally detected on emergency chest computed tomography (CT) scans performed for non-breast-related symptoms, and to explore reasons for the detection or oversight of these lesions.

A total of 73 chest CT examinations of 64 female patients, performed in the emergency department for non-breast-related complaints, were retrospectively evaluated. Breast Imaging and Reporting Data System (BI-RADS) 4 and BI-RADS 5 lesions with histopathological diagnoses of malignancy were included. The CT scans were re-evaluated for lesion size, location, laterality, breast parenchymal pattern, and the presence of axillary lymphadenopathy and skin thickening. Lesions were classified as "detected" or "missed" based on the initial emergency CT report, and detection factors were statistically compared between the two groups.

Of the 73 chest CT examinations, a discrete breast mass or a focal asymmetric breast tissue density was detected in 22 (30.1%), while it was missed in 51 (69.9%) CT scans with a diagnostic delay of 15.0±6.4 months (mean±SD) (range 4-33 months). The mean size of missed lesions was 13.6 mm (7.1-26.7 mm), significantly smaller than that of detected lesions at 22.2 mm (10.0-35.9 mm) (Student's t-test p < 0.001). The presence of axillary lymphadenopathy (p = 0.008) and a fatty (Type A) breast parenchymal pattern (p = 0.005) were statistically more frequent in detected cases. Missed lesions were more commonly located in the right breast (p = 0.026) and detected lesions were more commonly located in the inner zone (p = 0.014).

A high percentage of incidental breast malignancies are missed on emergency chest CTs, leading to significant diagnostic delays. Lesion size was the strongest determinant of detectability, while lesion location, breast parenchymal pattern, and axillary lymphadenopathy were also associated with lesion detection.