[Chondrosarcomatous metaplastic carcinoma of the breast, a rare tumor]. / Carcinoma metaplásico condrosarcomatoide de mama, una entidad inusual.

Metaplastic carcinomas of the breast are uncommon, accounting for less than 0.2% of all breast cancers. Clinically and radiologically, metaplastic carcinomas are indistinguishable from typical ductal carcinomas, and the diagnosis is made histologically by the finding of a mesenchymal component. We present a case of chondrosarcomatous metaplastic breast carcinoma whose definitive diagnosis required immunohistochemical techniques to confirm the malignant epithelial component of the tumor. Accurate diagnosis is important because this tumor behaves differently: it usually spreads through the blood (whereas typical epithelial carcinomas spread through the lymph vessels), metastases present during follow-up rather than before diagnosis, and the five-year survival rate is 35%.