CS Extension

Notes

**Note 1**: Periosteum is a fibrous membrane that wraps the outer surface of bones. Mucoperiosteum is a compound structure of mucous membrane and periosteum. Cortical bone is the dense compact outer layer of bone.Trabecular, cancellous, or spongy bone (spongiosa) is a porous network of tissue filling the interior of bone, decreasing weight and allowing room for blood vessels and marrow. **Note 2**: AJCC assigns the T category based on size when bone involvement is limited to the cortex. Involvement through cortical bone is required for assignment of T4a. **Note 3**: The assignment of T1, T2 , and T3 categories for tumors of the lip and oral cavity is based on tumor size. A physician's statement of the T category may be used to code CS Tumor Size and/or CS Extension if this is the only information in the medical record regarding one or both of these fields. However the two fields are coded independently: for example the record may document size but not extension, other than the physician's statement of the T category. Use codes 405, 410, 415, 775, 810, or 815 as appropriate to code CS Extension based on a statement of T when no other extension information is available. **Note 4**: Use code 300 for localized tumor only if no information is available to assign code 100, 400, 405, 410, or 415.

Code	Description	AJCC 7 T	AJCC 6 T	Summary Stage 1977 T	Summary Stage 2000 T
000	In situ, intraepithelial, noninvasive	Tis	Tis	IS	IS
100	Invasive tumor on one side confined to mucoperiosteum (stroma)	Extension Size	Extension Size	L	L
300	Localized, NOS	Extension Size	Extension Size	L	L
400	Tumor crosses midline	Extension Size	Extension Size	L	L
405	Stated as T1 with no other information on extension	Extension Size	Extension Size	L	L
410	Stated as T2 with no other information on extension	Extension Size	Extension Size	L	L
415	Stated as T3 with no other information on extension	Extension Size	Extension Size	L	L
500	Buccal mucosa (inner cheek) Gingiva, upper Glossopalatine arch Pharyngopalatine arch Soft palate including uvula	Extension Size	Extension Size	RE	RE
535	Cortical bone of maxilla Cortical palatine bone Maxilla, NOS Palatine bone, NOS Cortical bone, NOS (not specified in higher codes) Bone, NOS (not specified in higher codes)	Extension Size	Extension Size	RE	RE
700	OBSOLETE DATA REVIEWED AND CHANGED V0203 CSv2 codes differentiate between involvement of cortical bone and trabecular bone. All CSv1 cases should be reviewed and recoded to 535 or 725 as appropriate. Maxillary bone Palatine bone	ERROR:	ERROR:	ERROR:	ERROR:
725	Trabecular bone: Maxilla Palatine bone	T4a	T4a	RE	RE
740	OBSOLETE DATA REVIEWED AND CHANGED V0203 Recode involved structures to code 745, 750, 765, or 800 as appropriate. Deep muscle of tongue Floor of nose Maxillary sinus (antrum) Nasal cavity Nasopharynx Skin of face Sphenoid bone	ERROR:	ERROR:	ERROR:	ERROR:
745	Floor of nose Maxillary sinus (antrum) Nasal cavity Nasopharynx	T4a	T4a	D	D
750	Deep (extrinsic) muscle of tongue: Genioglossus Hyoglossus Palatoglossus Styloglossus	T4a	T4a	D	D
760	OBSOLETE DATA CONVERTED V0200 See code 790 Pterygoid plates	ERROR:	ERROR:	ERROR:	ERROR:
765	Skin of face	T4a	T4a	D	D
775	Stated as T4a with no other information on extension	T4a	T4a	RE	RE
788	Specified bone (Other than maxilla, palatine, and bones in codes 790 and 800)	T4b	T4a	D	D
790	Masticator space Pterygoid plates	T4b	T4b	D	D
800	Further contiguous extension: Skull base including sphenoid bone other than pterygoid plates Internal carotid artery (encased)	T4b	T4b	D	D
810	Stated as T4b with no other information on extension	T4b	T4b	D	D
815	Stated as T4 [NOS] with no other information on extension	T4NOS	T4NOS	RE	RE
950	No evidence of primary tumor	T0	T0	U	U
999	Unknown; extension not stated Primary tumor cannot be assessed Not documented in patient record	TX	TX	U	U

- For CS Extension codes 100-535 ONLY, the T category for AJCC 7 staging is assigned based on the value of CS Tumor Size, as shown in the Extension Size Table for this schema. - For CS Extension codes 100-535 ONLY, the T category for AJCC 6 staging is assigned based on the value of CS Tumor Size, as shown in the Extension Size Table for this schema.