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 involvement is limited to cortical bone. 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 (buccinator)	Extension Size	Extension Size	RE	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	Lip(s) including commissure	Extension Size	Extension Size	RE	RE
510	Gingiva	Extension Size	Extension Size	RE	RE
525	Cortical bone of mandible Cortical bone of maxilla Mandible, NOS Maxilla, NOS Cartilage, NOS Cortical bone, NOS (not specified in higher codes) Bone, NOS (not specified in higher codes)	Extension Size	Extension Size	D	D
550	Subcutaneous soft tissue of cheek	Extension Size	Extension Size	RE	RE
600	Lateral pharyngeal wall Tonsillar pillars and fossae Tonsils	Extension Size	Extension Size	RE	RE
603	600 + 550	Extension Size	Extension Size	RE	RE
605	(550 or 600) + 525 Any structure in code 550 or 600 plus any structure in code 525	Extension Size	Extension Size	D	D
620	Hard palate including cortical palatine bone Soft palate	Extension Size	Extension Size	D	D
650	OBSOLETE DATA CONVERTED V0200 Assign to T1-3 category per curator, see code 550 Subcutaneous soft tissue of cheek	ERROR:	ERROR:	ERROR:	ERROR:
660	Skin of cheek with or without ulceration	T4a	T4a	RE	D
665	660 + (525 or 620) Skin of cheek plus any structure in code 525 or 620	T4a	T4a	D	D
670	OBSOLETE DATA CONVERTED V0200 See code 740 Maxillary sinus	ERROR:	ERROR:	ERROR:	ERROR:
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 525, 605, 665, 725, or 753 as appropriate. Bone (cortical): Mandible Maxilla	ERROR:	ERROR:	ERROR:	ERROR:
725	Trabecular bone: Mandible Maxilla Palatine bone	T4a	T4a	D	D
730	OBSOLETE DATA CONVERTED V0200 See code 805 Skull	ERROR:	ERROR:	ERROR:	ERROR:
740	Maxillary sinus (antrum) Nasal cavity	T4a	T4a	D	D
750	Tongue Deep (extrinsic) muscle of tongue: Genioglossus Hyoglossus Palatoglossus Styloglossus	T4a	T4a	D	D
753	(725, 740, or 750) + 620	T4a	T4a	D	D
755	Stated as T4a with no other information on extension	T4a	T4a	RE	D
788	Specified bone (Other than maxilla, mandible, palatine, or bones in codes 795 and 805)	T4b	T4b	D	D
790	OBSOLETE DATA RETAINED V0200 Other contiguous extension: Base of skull Encases internal carotid artery Masticator space Pterygoid plates	ERROR:	T4b	D	D
795	Masticator space Pterygoid plates	T4b	T4b	D	D
800	OBSOLETE DATA REVIEWED AND CHANGED V0203 Extension to hard palate and soft palate assigned to T1-T3 categories in CSv2 based on curator response. All CSv1 cases should be reviewed and recoded to 620, 665, 753, or 808 as appropriate. Further contiguous extension: Hard palate Soft palate	ERROR:	ERROR:	ERROR:	ERROR:
805	Further contiguous extension including: Internal carotid artery (encased) Base of skull Skull	T4b	T4b	D	D
808	(788, 795, or 805) + 620	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	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 100-620 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 100-620 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.