三阴性乳腺癌（TNBC）指的是一组异质的癌症，其具有更具侵袭性的生物特征、更快的生长速度以及早期远处转移和复发倾向，与其他乳腺癌亚型相比。由于TNBC的侵袭性和快速生长，其及时准确的诊断存在特定的影像挑战。最初，TNBC通常表现为局限性肿块，因此缺乏原发乳腺恶性肿瘤的典型特征，如不规则形状、有棘突尖顶边缘和脱分化反应。鉴于可能的误解，对TNBC多模态影像外观的审查对于指导放射科医师区分TNBC与良性病变至关重要。与作为筛查检出的癌症不同，TNBC通常在临床上表现为可触及的区域，最常对应于乳腺X线摄影、超声和MRI上的离散肿块。界限清晰和低回声至无回声回声特征的组合可能导致将TNBC误解为良性纤维腺瘤或囊肿。因此，通过仔细的乳腺X线摄影和超声评估，并进行超声图像优化，可以避免误解。放射科医师应识别出可以模仿良性实体的TNBC特征，以及应引起对恶性的关注的细微特征，以帮助及时准确地诊断TNBC。©RSNA，2023本文的测验问题可在补充资料中获得。

Triple-negative breast cancer (TNBC) refers to a heterogeneous group of carcinomas that have more aggressive biologic features, faster growth, and a propensity for early distant metastasis and recurrence compared with other breast cancer subtypes. Due to the aggressiveness and rapid growth of TNBCs, there are specific imaging challenges associated with their timely and accurate diagnosis. TNBCs commonly manifest initially as circumscribed masses and therefore lack the typical features of a primary breast malignancy, such as irregular shape, spiculated margins, and desmoplastic reaction. Given the potential for misinterpretation, review of the multimodality imaging appearances of TNBCs is important for guiding the radiologist in distinguishing TNBCs from benign conditions. Rather than manifesting as a screening-detected cancer, TNBC typically appears clinically as a palpable area of concern that most commonly corresponds to a discrete mass at mammography, US, and MRI. The combination of circumscribed margins and hypoechoic to anechoic echogenicity may lead to TNBC being misinterpreted as a benign fibroadenoma or cyst. Therefore, careful mammographic and sonographic evaluation with US image optimization can help avoid misinterpretation. Radiologists should recognize the characteristics of TNBCs that can mimic benign entities, as well as the subtle features of TNBCs that should raise concern for malignancy and aid in timely and accurate diagnosis. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.