What is the TNM classification for malignant melanoma?

Updated: Mar 23, 2020
  • Author: Winston W Tan, MD, FACP; Chief Editor: Dirk M Elston, MD  more...
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Answer

Answer

The American Joint Committee on Cancer (AJCC) tumor/node/metastasis (TNM) classification and staging system for cancer are provided below. [1, 2]  

Table 1. TNM Classification for Malignant Melanoma (Open Table in a new window)

Primary tumor (T)

TX

Primary tumor cannot be assessed (ie, curettaged melanoma)

T0

No evidence of primary tumor

Tis

Melanoma in situ

T1

Thickness ≤1.0 mm 

T1a: < 0.8 mm without ulceration 

T1b: < 0.8 mm with ulceration, or 0.8-1.0 mm with or without ulceration

T2

 Thickness >1.0-2.0 mm

T2a: Without ulceration

T2b: With ulceration

T3

Thickness >2.0-4.0 mm

T3a: Without ulceration

T3b: With ulceration

T4

Thickness >4.0 mm 

T4a: Without ulceration

T4b: With ulceration

Regional lymph nodes (N)

NX

Regional nodes cannot be assessed (ie, previously removed for another reason)

N0

No regional metastases detected

N1

One tumor-involved lymph node or in-transit, satellite, and/or microsatellite meastases with no tumor-involved nodes

N1a: One clinically occult (ie, detected by sentinel lymph node biopsy [SLNB]; no in-transit, satellite, or microsatellite metastases

N1b: One clinically detected; no in-transit, satellite, or microsatellite metastases

N1c: No regional lymph node disease; in-transit, satellite, and/or microsatellite metastases found

N2

Two or three tumor-involved nodes; or in-transit, satellite, or microsatellite metastases

N2a: Two or three clinically occult (ie, detected by SLNB); no in-transit, satellite, or microsatellite metastases

N2b: Two or three clinically detected; no in-transit, satellite, or microsatellite metastases

N2c: One clinically occult or clinically detected; in-transit, satellite, and/or microsatellite metastases found

N3

≥4 tumor-inolved nodes or  in-transit, satellite, and/or microsatellite metastases with ≥2 tumor-involved nodes or any number of matted nodes without or with in-transit, satellite, and/or microsatellite metastases 

N3a: ≥4 clinically occult (ie, detected by SLNB); no in-transit, satellite, or microsatellite metastases

N3b: ≥4, at least one of which was clinicallly detected, or presence of any matted nodes; no in-transit, satellite, or microsatellite metastases

N3c: ≥2 clinically occulr or clinically detected and/or presence of any matted nodes, with presence of in-transit, satellite, and/or microsatellite metastases

Distant metastasis (M)

M0

No detectable evidence of distant metastases

M1a

Metastases to skin, soft tissue (including muscle), and/or nonregional lymph nodes

M1b

Lung metastasis, with or without M1a involvement

M1c

Distant metastasis to non–central nervous system (CNS) visceral sites with or without M1a or M1b involvement

M1d

Distant metastasis to CNS, with or without M1a or M1b involvement

Cases of metastasis (beyond M0) in which the lactate dehydrogenase (LDH) level is known are given the suffix (0), for normal LDH level, or (1), for elevated LDH level

 

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