(1) Background: Ultrasound (US) elastography is an imaging technology that reveals tissue stiffness. This study aimed to investigate whether fibrotic focus (FF) affects elastographic findings in breast cancer, and to evaluate the clinical significance of US elastography and FF in breast cancer. (2) Methods: In this study, 151 patients with breast cancer who underwent surgery were included. Strain elastography was performed and an elasticity scoring system was used to assess the findings. The elasticity scores were classified as negative, equivocal, or positive. FF was evaluated in the surgical specimens. Medical records were reviewed for all patients. (3) Results: Elastographic findings were equivocal in 30 patients (19.9%) and positive in 121 patients (80.1%). FF was present in 68 patients (46.9%). There was no correlation between elastographic findings and FF. Older age, larger tumor size, lymph node metastasis, and higher tumor stage were associated with positive elastographic results. FF showed a positive correlation with age, postmenopausal status, tumor size, lymphovascular invasion, lymph node metastasis, tumor stage, and intratumoral and peritumoral inflammation. (4) Conclusions: Our study showed that positive elastographic results and FF were associated with poor prognostic factors for breast cancer. FF did not affect the elastographic findings of this study.

Purpose: This study aimed to analyze the association between fibrotic focus (FF) and tumor-infiltrating lymphocytes (TILs) and to determine the prognostic significance of FF and TILs in the breast according to its molecular subtypes.Methods: The study included patients who underwent surgical treatment for breast cancer, for whom tissue samples were available. FF within the tumor and TILs in breast cancer tissues were evaluated. Clinicopathological characteristics were reviewed from medical records.Results: FF and TILs were present in 31.3% and 81.7% of the patients, respectively. FF and TILs showed a positive correlation. FF were significantly associated with tumor size, lymphovascular invasion, regional lymph node metastasis, and tumor stage. TILs were significantly associated with menopausal status, histologic grade, tubule formation, nuclear grade, mitosis, human epidermal growth factor receptor 2 (HER2) overexpression, molecular subtype of breast cancer, and the number of cluster of differentiation 8+ T cells. In TIL-positive cases, FF were significantly associated with tumor size, regional lymph node metastasis, extranodal extension, lymphovascular invasion, tumor stage, recurrence-free survival, and overall survival (OS). Based on HER2 overexpression status, TILs were significantly associated with tumor size, tumor necrosis, histologic grade, estrogen receptor status, and epidermal growth factor receptor expression in HER2-negative breast cancer. Further, in HER2-negative breast cancer, OS and recurrence-free survival were significantly associated with FF. The OS of FF-positive patients was significantly shorter than that of FF-negative patients.Conclusion: Our study showed an association between FF and TIL levels in breast cancer, indicating that FF are associated with poor prognostic factors for breast cancer and poor OS, and that TILs are associated with HER2 overexpression. However, further studies are needed to elucidate the interactions between FF and TILs in breast cancer.