A case of matrix-producing carcinoma (MPC), which is a unique variant of breast cancer, is described with cytopathological and radiographical findings. A 75-year-old female presented with a palpable mass in her right breast. After confirmation of the cytopathological diagnosis, the patient received a right mastectomy with ipsilateral axillary lymph node dissection. The histopathological examination revealed MPC. The Union Internationalis Contra Cancrum postoperative clinical stage was IIB. The patient is well and without disease 18 months after the surgery.