CS Extension

Notes

**Note 1**: Periosteum is a fibrous membrane that wraps the outer surface of bones. Cortical bone is the dense compact outer layer of the 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, 755, 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, 200, 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 confined to: Lamina propria Submucosa	Extension Size	Extension Size	L	L
200	Musculature invaded	Extension Size	Extension Size	L	L
300	Localized, NOS	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	Adjacent oral cavity	Extension Size	Extension Size	RE	RE
535	Cortical bone of mandible Cortical bone of maxilla Mandible, NOS Maxilla, NOS Cortical bone, NOS (not specified in higher codes) Bone, NOS (not specified in higher codes)	Extension Size	Extension Size	D	D
600	Oropharynx Inferior surface of soft palate Lateral pharyngeal wall Lingual surface of epiglottis Vallecula	Extension Size	Extension Size	RE	RE
605	600 + 535 Any structure in 600 plus any structure in 535	Extension Size	Extension Size	D	D
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, 605, or 725 as appropriate. Extension to adjacent structures: Mandible Maxilla Maxillary antrum (sinus) Nasal cavity Skin of face/neck Tongue	ERROR:	ERROR:	ERROR:	ERROR:
705	Tongue	T4a	T4a	D	D
710	Deep (extrinsic) muscle of tongue: Genioglossus Hyoglossus Palatoglossus Styloglossus	T4a	T4a	D	D
720	OBSOLETE DATA CONVERTED V0200 See code 800 Skull	ERROR:	ERROR:	ERROR:	ERROR:
725	Trabecular bone: Mandible Maxilla Palatine bone	T4a	T4a	D	D
735	Maxillary antrum (sinus) Nasal cavity Skin of face/neck	T4a	T4a	D	D
750	OBSOLETE DATA RETAINED V0200 Base of skull Encases internal carotid artery Masticator space Pterygoid plates	ERROR:	T4b	D	D
775	Stated as T4a with no other information on extension	T4a	T4a	D	D
788	Specified bone (Other than maxilla, mandible, and bones in codes 790 and 800)	T4b	T4b	D	D
790	Masticator space Pterygoid plates	T4b	T4b	D	D
800	Further contiguous extension: Skull base 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	D	D
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 100-605 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 100-605 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.