CS Extension: Cheek (Buccal) Mucosa, Vestibule

Code	Description	TNM	SS77	SS2000
00	In situ; noninvasive; intraepithelial	Tis	IS	IS
10	Invasive tumor confined to: Lamina propria Submucosa	*	L	L
20	Musculature (buccinator)	*	RE	L
30	Localized, NOS	*	L	L
50	Lip(s) including commissure	*	RE	RE
51	Gingiva	*	RE	RE
60	Lateral pharyngeal wall Tonsillar pillars and fossae Tonsils	*	RE	RE
65	Subcutaneous soft tissue of cheek	T4a	RE	RE
66	Skin of cheek (with or without ulceration)	T4a	RE	D
67	Maxillary sinus	T4a	D	D
70	Bone (cortical): Mandible Maxilla	T4a	D	D
73	Skull	T4b	D	D
75	Tongue Deep extrinsic muscle of tongue	T4a	D	D
79	Other contiguous extension: Base of skull Encases internal carotid artery Masticator space Pterygoid plates	T4b	D	D
80	Further contiguous extension: Hard palate Soft palate	T4b	D	D
95	No evidence of primary tumor	T0	U	U
99	Unknown extension Primary tumor cannot be assessed Not documented in patient record	TX	U	U

* For Extension codes 10, 20, 30, 50, 51, and 60 ONLY, the T category is assigned based on the value of CS Tumor Size, as shown in the Extension Size Table for this site.