Could breast multiparametric MRI discriminate between pure ductal carcinoma in situ and microinvasive carcinoma?

BACKGROUND: Ductal carcinoma in situ (DCIS) is often reclassified as invasive cancer in the final pathology report of the surgical specimen. It is of significant clinical relevance to acknowledge the possibility of underestimating invasive disease when utilizing preoperative biopsies for a DCIS diagnosis. In cases where such histologic upgrades occur, it is imperative to consider them in the preoperative planning process, including the potential inclusion of sentinel lymph node biopsy due to the risk of axillary lymph node metastasis. PURPOSE: To assess the capability of breast multiparametric magnetic resonance imaging (MP-MRI) in differentiating between pure DCIS and microinvasive carcinoma (MIC). MATERIAL AND METHODS: Between January 2018 and November 2022, this retrospective study enrolled patients with biopsy-proven DCIS who had undergone preoperative breast MP-MRI. We assessed various MP-MRI features, including size, morphology, margins, internal enhancement pattern, extent of disease, presence of peritumoral edema, time-intensity curve value, diffusion restriction, and ADC value. Subsequently, a logistic regression analysis was conducted to explore the association of these features with the pathological outcome. RESULTS: Of 129 patients with biopsy-proven DCIS, 36 had foci of micro-infiltration on surgical specimens and eight were diagnosed with invasive ductal carcinoma (IDC). The presence of micro-infiltration foci was significantly associated with several MP-MRI features, including tumor size (P <0.001), clustered ring enhancement (P <0.001), segmental distribution (P <0.001), diffusion restriction (P = 0.005), and ADC values <1.3 × 10-3 mm2/s (P = 0.004). CONCLUSION: Breast MP-MRI has the potential to predict the presence of micro-infiltration foci in biopsy-proven DCIS and may serve as a valuable tool for guiding therapeutic planning.

Revisiting Nonmass Enhancement in Breast MRI: Analysis of Outcomes and Follow-Up Using the Updated BI-RADS Atlas.

OBJECTIVE: The purpose of this study is to assess the frequency of reclassification of nonmass enhancement (NME) as background parenchymal enhancement (BPE) and to determine positive predictive values (PPVs) of NME descriptors using the revised BI-RADS atlas. MATERIALS AND METHODS: A retrospective review of our institution's MRI database from January 1, 2009, through March 30, 2012, identified 6220 contrast-enhanced breast MRI examinations. All findings prospectively assessed as NME and rated as BI-RADS categories 3, 4, and 5 (n = 386) were rereviewed in consensus by two radiologists who were blinded to pathologic findings with the fifth edition of the BI-RADS lexicon. Findings considered as postsurgical, associated with known cancers, NME given a BI-RADS category 3 assessment before 2009, previously biopsied, and those reclassified as BPE, focus, or mass were excluded (n = 181). Medical records were reviewed for demographics and outcomes. RESULTS: Two hundred five women were included (mean age, 48.8 years; range, 21-84 years). Seventy-seven of 386 findings (20.0%) were reclassified as BPE, and patients with BPE were younger than those with NME (mean age, 43.9 years; range, 31-62 years) (p = 0.003). Pathology results for 144 of 205 (70.2%) patients included 52 malignant, 11 high-risk, and 81 benign lesions. The highest PPVs for distribution patterns were 34.5% (10/29) for segmental and 100.0% (3/3) for diffuse distribution. The highest PPVs for internal enhancement patterns were 36.7% (11/30) for clustered ring enhancement and 27.5% (11/40) for clumped enhancement. No difference for NME malignancy rate was noted according to BPE (10/52 [19.2%] marked or moderate; 42/153 [27.5%] mild or minimal, p = 0.24). Thirty-two percent (17/52) of malignant NMEs had high T2 signal. CONCLUSION: Careful assessment of findings as BPE versus NME can improve PPVs, particularly in younger women. Although clustered ring enhancement had one of the study's highest PPVs, this number falls below previously published rates. Reliance on T2 signal as a benign feature may be misleading, because one-third of malignancies had T2 signal.

Differentiation between Clinically Noninflammatory Granulomatous Lobular Mastitis and Noncalcified Ductal Carcinoma in situ Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging.

INTRODUCTION: Challenges in differentiation between clinically noninflammatory granulomatous lobular mastitis (GLM) and noncalcified ductal carcinoma in situ (DCIS) remain. OBJECTIVE: To identify the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) characteristics contributing to their differential diagnosis. METHODS: A total of 33 clinically noninflammatory GLM and 36 noncalcified DCIS were retrospectively analyzed in the study. Internal enhancement of a nonmass enhancement (NME) lesion was divided into clustered enhanced ring (absence/presence), and clustered enhanced ring (presence) was further classified as small and large ring based on the optimal cutoff value. The 5th Breast Imaging and Data System MRI descriptors were used for assessing the other DCE-MRI characteristics. Multivariate analysis including variables with significant differences in univariate analyses was conducted to identify the independent predictors. The discriminative abilities of different predictors and their combination were compared by area under the receiver-operating characteristic curves (AUCs). RESULTS: An NME lesion was seen more commonly in clinically noninflammatory GLM than in noncalcified DCIS (p = 0.003). DCE-MRI characteristics with significant differences in univariate analyses included NME size, clustered enhanced ring (absence/presence), ring size, initial increase and kinetic characteristics for the differentiation between these two entities presenting as NME lesion. Clustered enhanced ring (presence) was further classified as small (≤7 mm) or large ring (>7 mm). Multivariate analysis revealed that internal enhancement and initial increase were identified as significant independent predictors, and the AUC of their combination achieved the highest value of 0.867 (95% CI, 0.748-0.943). CONCLUSIONS: An NME lesion with a large ring is more highly suggestive of clinically noninflammatory GLM.

Magnetic resonance imaging characteristics of granulomatous mastitis.

Granulomatous mastitis (GM) is a benign chronic inflammatory condition of the breast. This study was performed to determine the utility of magnetic resonance imaging (MRI) in differentiating GM from malignancy. MRI findings in 12 women with clinical or histopathologically-proven GM were retrospectively reviewed. Non-mass enhancement on MRI was present in all 12 patients with clustered ring enhancement being the most common pattern (n=7, 58%). Architectural distortion (n=10, 83%), skin thickening (n=10, 83%) and focal skin enhancement (n=10, 83%) were also very common. MRI features of GM are often identical to features considered suspicious for malignancy on MRI.

Clinics in diagnostic imaging (180). Ductal carcinoma in situ (DCIS).

A 26-year-old woman presented with a slow-growing right breast lump. Excision biopsy of the lump showed invasive ductal carcinoma with adjacent ductal carcinoma in situ (DCIS). Preoperative imaging was performed to assess the extent of disease. Magnetic resonance (MR) imaging of the breasts showed an area of clustered ring enhancement deep to the biopsy site, which was representative of residual DCIS. DCIS is a common noninvasive malignancy that manifests as a primary breast tumour or in association with other lesions. The radiological features of DCIS are discussed herein, with special attention to the clustered ring enhancement pattern on MR imaging.