Breast Imaging Findings of Microcalcifications in Ductal Carcinoma in Situ and Their Correlations with Pathological and Biological Features

Background: Mammography (MMG) is the primary screening tool for breast cancer, as microcalcifications are the most common MMG finding in ductal carcinoma in situ (DCIS). The use of high-frequency transducers facilitates the visualization of calcifications on ultrasonography (USG), especially in patients with dense breasts and cancer symptoms. Although a correlation has been reported between the imaging features of DCIS and pathological features, few studies have focused on multiple imaging modalities. Objectives: To evaluate the correlation of DCIS microcalcifications in breast imaging with pathological and biological features. Patients and Methods: The MMG and USG findings of 125 lesions detected in 123 patients, diagnosed with pure DCIS, were retrospectively reviewed according to the breast imaging-reporting and data system (BI-RADS). The USG and comparable MMG findings of microcalcifications were divided into three groups: group 1 (MMG negative, USG negative), group 2 (MMG positive, USG negative), and group 3 (MMG positive, USG positive). The pathological findings (nuclear grade and comedo necrosis) and biological features [estrogen (ER) positive group, human epidermal growth factor receptor 2 (HER2) positive group, triple negative group, and Ki-67 index] were compared with the MMG and USG features using Chi-square test. Results: Microcalcifications were observed on MMG in 83 (66.4%) DCIS lesions. Positive microcalcifications on MMG were significantly associated with a high nuclear grade (P = 0.001) and comedo necrosis (P = 0.001). Positive microcalcifications on MMG were significantly associated with ER negativity (P = 0.023), HER2 positivity (P = 0.002), and increased Ki-67 index (P = 0.001). There were 62 lesions (49.6%) without microcalcifications on USG (group 1 and group 2), while there were 63 (50.4%) lesions with microcalcifications on USG (group 3). Positive microcalcifications on MMG were significantly associated with ER-negative group (P = 0.023), HER2-positive group (P = 0.002), and increased Ki 67 index (P = 0.001). Conclusion: Based on the present results, DCIS microcalcifications detected via imaging were significantly associated with poor prognostic pathological factors, such as a high nuclear grade and comedo necrosis, as well as poor prognostic biological factors, including ER negativity, HER2 positive group, and a high Ki-67 index.