Stage II is divided into stages IIA, IIB, and IIC. In stage IIA, (1) the tumor is more than 1 but not more than 2 millimeters thick, with ulceration (a break in the skin); or (2) more than 2 but not more than 4 millimeters thick, with no ulceration. In stage IIB, (1) the tumor is either more than 2 but not more than 4 millimeters thick, with ulceration; or (2) more than 4 millimeters thick, with no ulceration. In stage IIC, the tumor is more than 4 millimeters thick, with ulceration.