[Sarcomatoid carcinoma in breast]

To observe the distinctive pathomorphological features of sarcomatoid carcinoma (SC) in mammary gland as well as its diagnosis and differential diagnosis.

1 538 malignant tumors of the breast were reviewed. 15 cases (0.98%) were diagnosed as SC. AE1/AE3, carcinoembryonic antigen (EMA), vimentin, S-100 protein, actin, estrogen receptor (ER) and progesterone (PR) were performed with SP immunohistochemical staining methods.

The SC were divided into four morphological types according to the distinctive features of their sarcomatoid components. (1) Polymorphic sarcoma type: sarcomatoid components are polymorphic; (2) Spindle cell type: sarcomatoid components consisted of spindle cells; (3) Osteoclastic giant cell type: a huge number of osteoclastic giant cells in the sarcomatoid components; (4) Myxocartilage type: myxocartilaginoid components are seen in the tumor tissue. With immunohistochemical staining, the expression rates of AE1/AE3, EMA, vimentin, S-100 protein and actins in the epithelial components were in 11, 15, 11, 12 and 8 cases respectively, and sarcomatoid components were in 10, 13, 13, 13 and 10 cases respectively, while ER and PR were positive only in 2 cases.

Sarcomatoid carcinoma of the breast should be distinguished from carcinosarcoma, desmoplastic carcinoma, sarcoma, nodular fasciitis and fibromatosis.