Abstract： To the editor:Primary lymphoma of the breast is extremely rare.Here we report a case of a diffuse large B-cell lymphoma in a 20-year-old female patient.Some of the sonographic features were similar to those of a carcinoma,and this lesion may have been easily misdiagnosed as breast cancer.A 20-year-old female presented with a one-month history of a rapid growth mass in her right breast.On clinical examination,a right-breast oval mass was palpated in the upper-outer quadrant,no tenderness,no adhesions with the skin,no orange peel-like changes,and no nipple retraction or elevation.In the right axillary region,enlarged lymph nodes were found,and there were no other enlarged superficial lymph nodes.Blood examination was normal,and urinalysis was negative.Chest X-ray and abdominal ultrasonography were also normal.Breast ultrasonography revealed a hypoechoic mass (size:3.8 cm × 1.8 cm × 1.4 cm) in the upper-outer quadrant with ill-defined boundaries and an irregular shape.The inner echo of the mass was heterogeneous and the posterior echo was substantially enhanced (Figure 1).