B3 Breast Lesions: Positive Predictive Value and Follow-Up on a Large Single-Institution Series

Area of Science:

• Breast pathology
• Oncology
• Surgical decision-making

Background:

• Lesions of uncertain malignant potential (B3) constitute 10% of core needle biopsies (CNBs) and vacuum-assisted breast biopsies (VABBs).
• Current practice often involves surgical excision for all B3 lesions.
• This study aims to refine management strategies by assessing malignancy risk within B3 subtypes.

Purpose of the Study:

• To investigate the association between specific B3 lesion subtypes and malignancy.
• To determine the positive predictive value (PPV) of malignancy for B3 lesions.
• To guide optimal clinical management of B3 lesions identified on breast biopsies.

Main Methods:

• Retrospective analysis of 226 patients with B3 lesions undergoing excisional surgery after CNB or VABB.
• Comparison of initial biopsy histology with final surgical pathology.
• Calculation of malignancy PPV using logistic regression and assessment of mammographic lesion characteristics.

Main Results:

• Malignancy was confirmed in 24.3% of B3 lesions, including ductal carcinoma in situ and invasive carcinoma.
• Atypical ductal hyperplasia (34.2%) and lobular intraepithelial neoplasia (27.5%) showed the highest rates of malignancy upgrade.
• Mammographic findings correlated significantly with final histology, and a 7-year follow-up revealed new carcinomas in 8.9% of patients.

Conclusions:

• Atypical ductal hyperplasia and lobular intraepithelial neoplasia among B3 lesions warrant surgical excision due to significant malignancy potential.
• Management for other B3 subtypes requires further investigation due to inconclusive data and wide confidence intervals.