Malignant phyllode tumor of the breast with features of intraductal carcinoma]

Malignant phyllode tumor is a rare biphasic breast tumor consisting of a malignant mesenchymal component and an epithelial component that is usually benign. We report an unusual case of a malignant phyllode tumor of the breast with neoplastic features of both the epithelial and stromal components. The patient was a 39-year-old woman with family history for breast carcinoma. Grossly, the excised tumor was a 9 x 7 x 5.5 cm gray lobulated mass with infiltrative margins and necrotic-hemorrhagic areas. Histologically the tumor consisted mainly of neoplastic mesenchyme with non invasive comedo, cribriform and micropapillary features of the ducts. Three months after the excision of the neoplastic mass, the patient developed an infiltrating ductal carcinoma of the opposite breast. Hereditary and bilateral tumors are commonly associated with germline mutations. Tissue from both neoplasms however did not express either BRCA1 or BRCA2 mutations.