Table Staging of Localized Melanoma Based on Thickness and Ulceration Stage Description 0 Intraepithelial or in situ melanoma IA ≤ 0.8 mm with no ulceration IB ≤ 0.8 - 1 mm with ulceration 0.8 - 2 mm with no ulceration IIA 1.01 - 2 mm with ulceration 2.01 - 4 mm with no ulceration IIB 2.01 - 4 mm with ulceration ≥ 4 mm with no ulceration IIC > 4 mm with ulceration Adapted from Amin MB, Edge SB, Greene FL, et al: AJCC Cancer Staging Manual, ed.