Xue Nianyu, Zhang Shengmin
Department of Ultrasound, Ningbo First Hospital, Ningbo, China.
Gland Surg. 2022 Oct;11(10):1722-1729. doi: 10.21037/gs-22-503.
The surrounding tissue of lesions located in the mammary fat layer is mainly fat, not mammary glands. Are the currently used Breast Imaging Reporting and Data System (BI-RADS) classifications and ultrasound elasticity appropriate for such lesions? In the present study, we discuss the value of elastography and BI-RADS classification in the evaluation of masses in the superficial fat layer of the breast.
Seventy-five breast masses within the fat layer that met inclusion criteria were included in the study. Using histopathology as the gold standard, we retrospectively analyzed whether the ultrasound elastography and BI-RADS classification results were consistent with the pathological results.
Histological analysis showed that 73 tumors were benign and 2 were malignant. According to the BI-RADS classification and treatment principle, 60% (45/75) of the masses were classified into category 4 and require breast biopsy. But only 4.4% (2/45) of these masses were malignant, and 95.6% (43/45) were overtreated. If we consider the masses with well-defined margins and within the fat layer on the surface of the breast glands as likely benign (BI-RADS category 3), the probability of malignancy is 1.4%. This is consistent with the BI-RADS classification probability of malignancy. According to this BI-RADS classification, only 1.3% (1/75) of patients required biopsy.
The findings of this study suggest that breast masses located in the fat layer are prone to be classified into category 4 by BI-RADS and thus be subjected to unnecessary biopsies. Ultrasound elastography can easily misdiagnose benign masses as malignant. It is suggested that ultrasound elastography can downgrade the BI-RADS classification, but not upgrade it. It is more reasonable for these breast masses to be classified as BI-RADS 3 for follow-up observation when the boundary is clear.
位于乳腺脂肪层的病变周围组织主要是脂肪，而非乳腺腺体。目前使用的乳腺影像报告和数据系统（BI-RADS）分类及超声弹性成像对此类病变是否适用？在本研究中，我们探讨弹性成像和BI-RADS分类在评估乳腺浅表脂肪层肿块中的价值。
本研究纳入了75个符合纳入标准的脂肪层乳腺肿块。以组织病理学作为金标准，我们回顾性分析超声弹性成像和BI-RADS分类结果是否与病理结果一致。
组织学分析显示，73个肿瘤为良性，2个为恶性。根据BI-RADS分类及治疗原则，60%（45/75）的肿块被分类为4类，需要进行乳腺活检。但这些肿块中只有4.4%（2/45）为恶性，95.6%（43/45）被过度治疗。如果我们将边界清晰且位于乳腺腺体表面脂肪层内的肿块视为可能为良性（BI-RADS 3类），则恶性概率为1.4%。这与BI-RADS分类的恶性概率一致。根据此BI-RADS分类，仅1.3%（1/75）的患者需要活检。
本研究结果表明，位于脂肪层的乳腺肿块容易被BI-RADS分类为4类，从而接受不必要的活检。超声弹性成像容易将良性肿块误诊为恶性。建议超声弹性成像可降低BI-RADS分类，但不能提高分类。当边界清晰时，将这些乳腺肿块分类为BI-RADS 3类进行随访观察更为合理。
