Source:http://linkedlifedata.com/resource/umls/id/C0278880
NCI: Stage I is divided into stages IA and IB. In stage IA, the tumor is not more than 1 millimeter thick, with no ulceration (a break in the skin). In stage IB, (1) the tumor is not more than 1 millimeter thick and it has ulceration; or (2) the tumor is more than 1 but not more than 2 millimeters thick, with no ulceration.,NCI: Stage I includes: IA (T1a, N0, M0); IB (T1b, N0, M0); (T2a, N0, M0). T1a: Melanoma is less than or equal to 1.0mm in thickness with or without ulceration. T1b: Melanoma is less than or equal to 1.0mm in thickness and level IV or V with ulceration. T2a: Melanoma 1.01-2.0 mm in thickness, no ulceration. N0: No regional lymph node metastasis. M0: No distant metastasis.-2003