Phyllodes tumor of the breast: role of CD10 in predicting metastasis.

BACKGROUND: Phyllodes tumors are classified as benign, borderline, and malignant according to a group of histological features. The expression of many biological markers has been explored to discriminate between different grades of phyllodes tumor and to predict their behavior. The immunohistochemical expression of CD10 has been shown to discriminate between benign and other grades of phyllodes tumor but has not been evaluated as a predictor of metastasis. The purpose of this study was to evaluate the usefulness of immunohistochemical staining of stromal CD10 in predicting the likelihood of metastasis in phyllodes tumors.

METHODS: The expression of CD10 was studied in 43 phyllodes tumors (16 benign, 10 borderline, and 17 malignant) using immunohistochemistry to evaluate whether differences in expression correlated with the presence of, and or, development of distant metastasis.

RESULTS: Metastasis occurred in six malignant phyllodes tumors. The expression of CD10 significantly (P<0.05) correlated with the occurrence of distant metastasis.

CONCLUSIONS: The expression of CD10 can be used to predict the occurrence of distant metastasis in phyllodes tumors of the breast.