答：诞腺肌上皮瘤是良性肿瘤，由肌上皮细胞构成，以往认为是多形性腺癌的一种亚型，Batsakis认为肌上皮瘤是一种单形性腺癌。其生物学行为与多形性腺瘤不同，肌上皮瘤的复发率低，不易发生癌变，预后较好。为此WHO1990年在诞腺肿瘤的分类中列为独立的肿瘤。肌上皮瘤的组织结构 A: The adenomyosis is a benign tumor composed of myoepithelial cells that was previously considered a subtype of pleomorphic adenocarcinoma. Batsakis believes that myoepithelioma is a type of mononuclear adenocarcinoma. Its biological behavior and pleomorphic adenoma is different, myoepithelioma recurrence rate is low, not prone to cancer, the prognosis is good. To this end the WHO1990 in the classification of breast cancer is incorporated into the tumor. Myoepithelioma tissue structure