Stage II is divided into stages IIA, IIB, and IIC. In stage IIA, the tumor is either 1 to 2 millimeters thick, with ulceration; or 2 to 4 millimeters thick, with no ulceration. In stage IIB, the tumor is either 2 to 4 millimeters thick, with ulceration; or more than 4 millimeters thick, with no ulceration. In stage IIC, the tumor is more than 4 millimeters thick, with ulceration.
