Abstract:ABSTRACT Objective To analysis the reasons of ultrasonic misdiagnosis of breast diffuse large B cell lymphoma(large B-cell lymphoma diffuse,DLBCL). Methods The clinical and ultrasonic data of 20 patients with breast DLBCL diagnosed by pathology in our hospital were retrospectively analyzed,and the causes of ultrasonographic misdiagnosis were analyzed. Results The ultrasonic appearances of 20 cases of breast DLBCL were divided into mass type(12 cases) and diffuse type(8 cases). 9 cases of elastography showed soft or medium stiff lesions,and 1 case of contrast-enhanced ultrasound showed inhomogeneous enhancement. According to BI-RADS-US classification,19 cases were diagnosed as BI-RADS 4,including 4 cases of 4A,8 cases of 4B and 7 cases of 4C,1 case was diagnosed as BI-RADS 3. 5 cases were preoperative diagnosis of breast lymphomay by conventional ultrasound combined with contrast-enhanced ultrasound and elastography.10 cases were misdiagnosed as breast cancer. 4 cases were misdiagnosed as inflammatory lesions.Only 1 case was misdiagnosed as BI-RADS 3 and was concerned as breast hamartoma.Conclusion Breast DLBCL is easily misdiagnosed by ultrasound. It can improve the diagnostic accuracy by fully understanding the conventional ultrasound findings and combined with contrast-enhanced ultrasound and elastography.