Axillary surgery for breast cancer has continually evolved, with sentinel lymph node biopsy for clinically node-negative women with invasive breast cancer having long replaced axillary lymph node dissection. The information obtained from axillary staging has been important in providing prognostic information and guiding adjuvant treatment recommendations. However, recent studies suggest that sentinel lymph node biopsy should be omitted in select low-risk patients whose axillary surgery provides minimal prognostic value. This was highlighted by the Society of Surgical Oncology Choosing Wisely Guidelines, advocating against routine axillary staging in older women with early-stage hormone receptor-positive breast cancer. Since the guideline release, ongoing research has continued to identify the subset of low-risk patients who would benefit from the omission of axillary staging and improve adherence to Choosing Wisely to prevent overtreatment in older people.

High-risk breast lesions including incidental intraductal papilloma without atypia (IPA), lobular hyperplasia (LCIS or ALH), flat epithelial atypia (FEA) and complex sclerosing lesion (CSL) are not routinely excised due to low upgrade rates to carcinoma. We aim to identify features of these lesions predictive of upgrade when identified concurrently with invasive disease. Methods: A single-center retrospective cohort study was performed for patients who underwent multi-site lumpectomies with invasive disease at one site and a high-risk lesion at another site between 2006 and 2021. A multinomial logistic regression was performed. Results: Sixty-five patients met the inclusion criteria. Four patients (6.2%) had an upgrade to in situ disease (DCIS) and one (1.5%) to invasive carcinoma. Three upgraded high-risk lesions were ipsilateral to the concurrent carcinoma and two were contralateral. In the multivariate model, a high-risk lesion within 5 cm of an ipsilateral malignancy was associated with increased risk of upgrade. The 3.8% upgrade rate for high-risk lesions located greater than 5 cm from ipsilateral malignancy or in the contralateral breast suggests that omission of excisional biopsy may be considered. Excisional biopsy of lesions within 5 cm of ipsilateral malignancy is recommended given the 25% upgrade risk in our series.

Pleomorphic lobular carcinoma in situ (PLCIS), a more aggressive variant of classic LCIS (CLCIS), demonstrates higher rates of upgrade to invasive carcinoma at surgical excision. Mammography may underestimate disease extent, whereas MRI may delineate lesions due to sensitivity. Our institutional pathology database was queried for patients diagnosed with PLCIS on core needle biopsy (CNB) from 2002 to 2025 who underwent surgical excision. Preoperative MRI and MRI-guided biopsies were reviewed. Radiologic, pathologic, surgical, and outcome data were collected. Proportions were summarized with 95% confidence intervals. Fisher's exact test assessed associations between categorical variables, and Bayesian logistic regression evaluated the relationship between calcification size and malignant upgrade. Preoperative MRI was performed in 94.7% (18/19) of patients. Among these, 61.1% (11/18) underwent additional biopsy, identifying additional LCIS in 72.7% (8/11), benign findings in 18.2% (2/11), and malignancy in 9.1% (1/11). Mammographic PLCIS presentation included calcifications (26.3%), mass (5.3%), both (31.6%), or neither (36.8%). Among cases with calcifications, 45.5% (5/11) upgraded to malignancy. Increasing calcification size was associated with higher upgrade probability (OR 1.32 per cm, 95% CrI: 0.68-2.97), increasing from 35% at 0.5 cm to 52% at 3.0 cm. The overall upgrade rate was 47.4% (9/19). Preoperative MRI in PLCIS frequently prompts additional biopsies, often detecting further LCIS rather than malignancy. Calcification extent predicts upgrade, and the high upgrade rate supports surgical excision after CNB diagnosis.