Histological type:1.adeno ca 2.mucinous ca(mucin>50%) 3.signet call ca 4.squanous ca 5.adenosquamous ca 6.small cell ca 7.undifferentiated ca 8.carcinoma NOS 9.carcinoid 10.leiomyosarcoma 11.lymphoma 12.adenocarcinoid 13 others