Sá RS, Logullo AF, Elias S, et al. - Researchers aimed at determining the rate of histologic underestimation (histopathologic results upgraded to invasive carcinoma after surgery) and the rate of positive results of sentinel lymph node biopsy (SLNB) in patients diagnosed with ductal carcinoma in situ (DCIS) in a Brazilian public hospital. Among a total of 86 included women, most had microcalcifications as the primary radiological lesion (73.2%), and underwent preoperative biopsy, with 21 (24.4%) having identification of an invasive component in the final pathology report. Invasive carcinoma of no special type (NST) was identified in most: 52.3% (n = 11) and microinvasive tumors (7 cases, 33.3%). Nodular lesion (61.9%) and an ultrasonography-guided biopsy (71.4%) were identified to be the main factors linked with histologic underestimation. Overall findings suggest that among patients with DCIS, the “histologic underestimation” rate was not low, and less than 5% of patients who underwent SLNB had axillary positivity. As per these results, SLNB should be performed in patients who have DCIS and a high risk of invasion and undergoing mastectomy. Among patients who will undergo lumpectomy, omission of SLNB could be considered and SLNB could be conducted if patients have upgraded to invasive breast cancer.