Heterologous Metaplastic Carcinoma
Metaplastic breast carcinoma consisting predominantly of undifferentiated spindle cell elements and high-grade chondrosarcoma. Rare foci of adenosquamous differentiation were present in some of the sections. When metaplastic carcinomas spread to distant site, the metastatic deposits may be composed entirely of epithelial/glandular elements, mesenchymal elements, or a combination of the two. When metaplastic breast carcinomas with chondroid or osseous differentiation spread to the bone, their distinction from primary bone tumors can be exceedingly difficult.