stage I Merkel cell carcinoma(stayj ... MER-kul sel KAR-sih-NOH-muh) Stage I Merkel cell carcinoma is divided into stages IA and IB. In stage IA, the tumor is 2 centimeters or smaller at its widest point and no cancer is found when the lymph nodes are checked under a microscope. In stage IB, the tumor is 2 centimeters or smaller at its widest point and no swollen lymph nodes are found by a physical exam or imaging tests. |