Cutaneous Squamous Cell Carcinoma of the Head and Neck

Table 2

AJCC TNM staging for cSCC [39].

Primary tumor (T)
TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
Tis: Carcinoma in situ
T1: Tumor 2 cm or less in greatest dimension with less than two high-risk features*
T2: Tumor greater than 2 cm in greatest dimension or tumor any size with two or more high-risk features**
T3: Tumor with invasion of maxilla, orbit, or temporal bone
T4: Tumor with invasion of skeleton (axial or appendicular) or perineural invasion of skull base
Regional Lymph Nodes (N)
NX: Regional lymph nodes cannot be assessed
N0: No regional lymph nodes
N1: Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension
N2a: Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension
N2b: Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension
N2c: Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
N3: Metastasis in a lymph node, more than 6 cm in greatest dimension
Distant Metastasis (M)
M0: No distant metastasis
M1: Distant Metastasis

*Excludes cSCC of the eyelid.
**High-Risk Features for the Primary Tumor (T) staging: Depth/Invasion: >2 mm thickness, Clark level ≥IV; perineural invasion, Anatomic Location: Primary site ear, Primary site hair-bearing lip, and Differentiation: Poorly differentiated or undifferentiated.