Background/Objectives: Breast abscesses and necrotic masses often show similar peripheral enhancement and a fluid-containing appearance on breast MRI, leading to diagnostic confusion. Accurate differentiation is critical because biopsies that fail to sample the lesion wall may yield false-negative results, may be misinterpreted as an infectious process, and delay diagnosis. Incorporating SWI into the protocol can provide additional clues to malignancy and, when warranted, prompt a second wall-targeted biopsy, thus reducing the risk of delayed cancer diagnosis. Methods: This single-center prospective diagnostic accuracy study included 42 female patients diagnosed between 2022 and 2025 with either necrotic breast tumors or abscesses, confirmed by histopathology. SWI-based Intralesional Susceptibility Score (ILSS), rim morphology, and mean ADC values were evaluated. Statistical analyses included the Mann–Whitney U test, chi-square test, ROC analysis, DeLong test for comparison of AUCs, and Cohen’s kappa for interobserver agreement. Results: SWI-based ILSS values were significantly higher in necrotic tumors compared to abscesses (mean ILSS: 2.28 vs. 0.85; 95% CI: 1.0–2.0; p < 0.001). Smooth hypointense rims were predominantly observed in abscesses (Sensitivity: 63.1%, 95% CI: 0.38–0.83; Specificity: 88.9%, 95% CI: 0.65–0.98; p = 0.001). Incomplete rim morphology was more frequent in tumors (Sensitivity: 78.9%, 95% CI: 0.54–0.93; Specificity: 77.8%, 95% CI: 0.52–0.93; p < 0.001). The double rim sign was highly specific for abscesses (Specificity: 95.2%, 95% CI: 0.76–0.99 p = 0.002). Conclusions: SWI provides valuable morphological information in differentiating abscesses from necrotic tumors on breast MRI. When used in combination with ADC values, it can enhance diagnostic accuracy.

Bu vaka, sistemik malignite öyküsü bulunan bir hastada gelişen beyin metastazını tanımlamaktadır. MRG’de çevresel kontrastlanan, geniş vazojenik ödemle çevrili kitle görünümü tipiktir. Difüzyon ve perfüzyon bulguları metastatik özellikleri destekler. Tedavi; cerrahi, radyocerrahi ve sistemik tedavilerin kombinasyonunu içerir.

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