Small breast cancer (≤ 5 mm): Ultrasonographic features and clinical and pathological characteristics

Purpose To identify differences in ultrasonography (US) feature, clinical and pathological characteristicsincluding immunohistochemical characteristics between small breast cancer(pathologic size ≤ 5 mm) and large breast cancer (> 5 mm).Materials and Methods A total of 528 invasive breast cancer lesions in 475 patients were included.US features with clinical and pathological characteristics were evaluated according topathologic size. US Breast Imaging-Reporting and Data System findings and final assessmentswere recorded for each lesion. Standard references were based on surgical pathologies.Results Of 528 invasive breast cancer lesions, 62 were small breast cancers. Small breast cancersshowed a higher rate of oval, round shape, parallel orientation; circumscribed margin; andiso/solid and cystic echo pattern, with no posterior feature. The final assessment of category 4was also a dominant factor in small breast cancer. Early stage, asymptomatic state, and extensiveductal carcinoma in situ component were associated with small breast cancers.Conclusion Our results show that small breast cancers have less suspicious US features thanlarge breast cancers.