Metaplastic Carcinoma of the Left Breast with Extensive Chondroid Differentiation

Metaplastic breast carcinoma is very rare neoplasm which contains mixture of carcinomatous (epithelial) and sarcomatous (mesenchymal) elements in variable proportion. Metaplastic carcinoma with chondroid differentiation is even rarer. We report a case of metaplastic carcinoma with extensive chondroid differentiation as there is paucity of information regarding pathological features and clinical outcomes for these rare tumors. Tumor had characteristic definite areas of classic infiltrating duct carcinoma with abundant chondromyxoid matrix, focal areas of chondrosarcoma and cartilagenous metaplasia. Tumour cells were immunoreactive for S-100, ER, and PR. When pathologist encounter breast tumor with chondroid differentiation, careful gross sampling, histopathology and immunoreactivity for mesenchymal and epithelial component are most useful to differentiate metaplastic carcinoma from malignant phylloides tumors and malignant adenomyoepithelioma.