[名词解释] 病理缩复环(pathologic retraction ring)

关食管癌的描述中，错误的是() ["A．食管上段最常见","B．可见原位癌","C．亚硝胺与食管癌发生有关","D．可以多中心发生","E．鳞状细胞癌多见"] 胎盘剥离不全 胎盘粘连 脐带脱垂(prolapse of umbilical cord) 脐带帆状附着(cord velamentous insertion) 病理缩复环(pathologic retraction ring)