Locally advanced and metastatic breast cancer with cartilaginous and/or osseous metaplasia showing excellent response to chemotherapy.

Breast cancer with cartilaginous and/or osseous metaplasia is considered a rare disease, but several cases have been reported recently. We report a case of breast cancer with cartilaginous and/or osseous metaplasia that was StageIV,(T4bN0M1b (PUL)), on the basis of the Japanese General Rules for Clinical and Pathological Recording of Breast Cancer, which responded well to chemotherapy. A 58-year-old women visited our hospital with a chief complaint of a palpable breast mass that had increased in size in March 2002. It was 20 x 15 x 14 cm and occupied the entire right breast. Chest computed tomography (CT) demonstrated multiple lung metastases. Histology of the biopsy specimens revealed a spindle-shaped cell carcinoma. It was ER(-), PgR(-), and HER2/neu Score 0. CAF was given to the patient as preoperative chemotherapy. Five cycles of treatment yielded improvement at the primary site and improvement of the metastatic lung lesions, which was judged as a partial response. Subsequently, one cycle of weekly paclitaxel 80 mg/m2 and oral administration of 5'-DFUR 800 mg/day were given. In November 2002, the patient underwent a right simple mastectomy with whole-layer skin grafting from the abdomen. The final pathological diagnosis was a rare type of breast cancer with cartilaginous and/or osseous metaplasia. Preoperative chemotherapy had caused necrosis in most of the tumor cells, and the efficacy was judged as Grade 2. From the third week postoperatively, weekly paclitaxel (80 mg/m2) was given. Six months after the operation, the multiple lung metastases were completely eliminated and new metastasis to liver or bone or local recurrence have not been observed.