Unveiling the histopathologic spectrum of MRI-guided breast biopsies: an institutional pathological-radiological...

Breast magnetic resonance imaging (MRI) has high sensitivity but suffers from low specificity, resulting in many benign breast biopsies for MRI-detected lesions. We sought to compare histologic findings between patients who underwent MRI-guided breast biopsy versus biopsy via other imaging modalities as well as to examine features associated with malignancy in the MRI cohort to help inform MRI-biopsy practice.

A 2-year (2018-2019) retrospective review of breast biopsies at our enterprise was conducted. Biopsies were categorized as stereotactic, ultrasound, MRI, or palpation guided. Pathology was categorized as benign (further divided into nine categories), atypical, or malignant (subdivided into in situ and invasive carcinoma). Pathology was compared between biopsy groups. Clinical, pathologic, and imaging features were compared between pathology groups within the MRI cohort.

5828 biopsies from 4154 patients were reviewed, including 548 MRI-guided biopsies with stratification of MRI-biopsy pathology as follows: 69% benign, 13.8% atypical, and 17.2% malignant. Among benign MRI biopsies, there was higher frequency of "clustered cysts with papillary apocrine metaplasia" (56/548; 10.2%) and lower rate of fibroadenoma/fibroadenomatous change (55/548; 10%) compared to other modalities (158 or 3% and 1144 or 21.7% of 5280 biopsies, respectively). Multivariate analysis revealed indication of breast cancer (p < .0001), ipsilateral cancer (p < .0001) and rapid initial phase kinetics (p = .017) to remain significantly associated with malignant MRI-biopsy pathology.

A concurrent or recent breast cancer diagnosis was most predictive of malignancy on MRI-guided breast biopsy. Combined MRI feature evaluation and radiologic-pathologic concordance activities may allow for prognostic refinement and improved risk stratification.