Electron microscopy of 3 cases showed evidences of polymorphism in differentiation of the tumor cells, including the transitional apperance into ducts, acinus, and endocrine cells. Weibel Palade body found in tumor cells in one out of 8 cases.

• 电镜下3 例均显示多形性分化，即肿瘤细胞分别向导管、腺泡和内分泌细胞分化，1 例肿瘤细胞内见到Weibel?Palade 小体。