Matrix-producing carcinoma of the breast showing retained rim enhancement to the late phase on magnetic resonance imaging.

A 54-year-old woman with a left breast mass was referred to our hospital. Mammography showed a mass, 2.1cm in size, with micro-lobulated boarders. Ultrasonography showed an oval mass with predominant low internal echoes and enhanced posterior echoes. Core needle biopsy of the tumor showed malignant cells and chondroid matrices. With MRI, the tumor was hypo-intense on T1-weighted images, mixed hyper- and hypo-intense on T2-weighted images, and completely rim enhanced until late phase on time-signal intensity curve. Despite the good indication for breast conserving therapy, patient's preference made her undergo total mastectomy, sentinel lymph node biopsy, and immediate breast reconstruction using an extended latissimus dorsi musculocutaneous flap. Postoperative pathologic study showed large acellular areas, atypical cells growing in cord-like and linear fashions with cartilage-like matrices, and no spindle cells / osteoclasts between the cancer cells and chondroid matrices, leading to the pathologic diagnosis of matrix-producing carcinoma. The patient received dose-dense chemotherapy as an adjuvant therapy and has been well without any recurrences for 14 months. Physicians should note that partial hypo-intensity on T2-weighted images and retained rim enhancement to the late phase should be important findings of breast matrix-producing carcinoma.