Benign Breast Phyllodes Tumor

**Semantic type:** Neoplastic Process

**Definition:** A usually unilateral, benign and well circumscribed biphasic neoplasm that arises from the breast. It usually affects middle-aged women. It is characterized by the presence of a double layer of epithelial cells that are arranged in clefts, surrounded by a cellular, monomorphic spindle cell mesenchymal component. Mitoses are rare. Necrotic changes may be present in large tumors.

**Synonyms:** - Benign Phyllodes Neoplasm of Breast - Benign Phyllodes Neoplasm of the Breast - Benign Phyllodes Tumor of Breast - Benign Phyllodes Tumor of the Breast - Breast Benign Phyllodes Neoplasm