[Sarcomatoid carcinoma in breast].

OBJECTIVE: To observe the distinctive pathomorphological features of sarcomatoid carcinoma (SC) in mammary gland as well as its diagnosis and differential diagnosis. METHODS: 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. RESULTS: 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. CONCLUSION: Sarcomatoid carcinoma of the breast should be distinguished from carcinosarcoma, desmoplastic carcinoma, sarcoma, nodular fasciitis and fibromatosis.