Complete Spontaneous Regression of Primary Diffuse Large B-Cell Lymphoma of the Breast

A healthy 69-year-old woman presented with a 4-week history of an elastic hard lump in the upper aspect of her left breast. Physical examination demonstrated a 4-cm, elastic, hard mass located in the midportion above the nipple of her left breast. Axillary lymphadenopathy was not found. There was no significant past medical history, and she was not taking any medication. Family history was negative for malignant disease. Mammography of the left breast showed a dense mass with an ill-defined border. Ultrasonography revealed a hypoechoic lesion, measuring 47 46 20 mm with an irregular margin. These diagnostic imaging findings suggested a malignant tumor. Further examination was by magnetic resonance imaging (MRI), and core needle biopsy (CNB) was performed to determine the histopathologic diagnosis. MRI (gadolinium-enhanced fatsuppressed T1-weighted imaging) showed high-contrast rim enhancement of the lesion and rapid washout on the time-intensity curve (Fig 1A).