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Melanoma Treatment (PDQ®)

  • Updated: 11/07/2014

Table 3. TNM Definitions for Stage I Melanoma

Stage TNM Description Image 
ClinicalaPathologicalb
Enlarge
Two-panel drawing of stage I melanoma. The first panel shows a stage IA tumor that is not more than 1 millimeter thick, with no ulceration (break in the skin). The second panel shows two stage IB tumors. One tumor is not more than 1 millimeter thick, with ulceration, and the other tumor is more than 1 but not more than 2 millimeters thick, with no ulceration. Also shown are the epidermis (outer layer of the skin), the dermis (inner layer of the skin), and the subcutaneous tissue below the dermis.
Stage I melanoma.
IAIAT1aMelanomas ≤1.0 mm in thickness without ulceration; mitosis <1/mm2
N0No regional metastases detected
M0No detectable evidence of distant metastases
IBIBT1bMelanomas ≤1.0 mm in thickness with ulceration or mitoses ≥1/mm2
T2aMelanomas 1.01–2.0 mm in thickness without ulceration
N0No regional metastases detected
M0No detectable evidence of distant metastases

T = primary tumor; N = regional lymph nodes; M = distant metastasis.
Adapted with permission from AJCC: Melanoma of the skin. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 325-44.
The explanations for superscripts a and b are at the end of Table 7.