Contrast-Enhanced Mammographic Features of In Situ and Invasive Ductal Carcinoma Manifesting Microcalcifications Only: Help to Predict Underestimation?

SIMPLE SUMMARY: Mammography frequently detects the early breast cancers manifesting microcalcifications only. By means of mammographically guided vacuum-assisted core needle biopsy, noninvasive ductal carcinoma in situ (DCIS) is often diagnosed. Unfortunately, invasive components are occasionally embedded within the noninvasive cancer bed, which will alter the preoperative planning. Whether or not to perform single-step sentinel lymph node sampling is an area of controversy. In order to minimize the overtreatment or undertreatment, we retrospectively reviewed the enhanced features of DCIS and invasive ductal carcinomas (IDCs) on contrast-enhanced spectral mammograms (CESMs). The CESM is a modern technique enabling the provision of conventional mammograms and contrast-enhanced images. The results of our study revealed low DCIS upgrade of the unenhanced DCIS. Otherwise, DCIS tended to appear as nonmass and pure ground glass enhancements, and IDC tended to appear as mass and unpurified solid enhancement. The enhanced features allow distinguishing DCIS and IDC. ABSTRACT: Background: The contrast-enhanced mammographic features of ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) manifesting microcalcifications only on mammograms were evaluated to determine whether they could predict IDC underestimation. Methods: We reviewed patients who underwent mammography-guided biopsy on suspicious breast microcalcifications only and received contrast-enhanced spectral mammography (CESM) within 2 weeks before the biopsy. Those patients who were proven to have cancers (DCIS or IDC) by biopsy and subsequently had surgical treatment in our hospital were included for analysis. The presence or absence, size, morphology and texture of enhancement on contrast-enhanced spectral mammography were reviewed by consensus of two radiologists. Results: A total of 49 patients were included for analysis. Forty patients (81.6%) showed enhancement, including 18 (45%) DCIS and 22 (55%) IDC patients. All nine unenhanced cancers were pure DCIS. Pure DCIS showed 72.22% nonmass enhancement and 83.33% pure ground glass enhancement. IDC showed more mass (72.2% vs. 27.8%) and solid enhancements (83.33% vs. 16.67%). The cancer and texture of enhancement were significantly different between pure DCIS and IDC, with moderate diagnostic performance for the former (p-value < 0.01, AUC = 0.66, sensitivity = 93%, specificity = 39%) and the latter (p-value < 0.01, AUC = 0.74, sensitivity = 65%, specificity = 83%). Otherwise, pure DCIS showed a significant difference in enhanced texture compared with upgraded IDC and IDC (p = 0.0226 and 0.0018, respectively). Conclusions: Nonmass and pure ground glass enhancements were closely related to pure DCIS, and cases showing mass and unpurified solid enhancements should be suspected as IDC. Unenhanced DCIS with microcalcifications only has a low DCIS upgrade rate. The CESM-enhanced features could feasibly predict IDC underestimation.