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 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 Tcategory 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, 780, 810, or 815 as appropriate to code CS Extension based on a statement of T when no other extenison 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: Lamina propria Submucosa	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	Anterior 2/3 of tongue Base of tongue Gingiva (alveolar ridge), lower Periosteum of mandible	Extension Size	Extension Size	RE	RE
530	Sublingual gland, including ducts Submandibular (submaxillary) glands, including ducts	Extension Size	Extension Size	RE	RE
535	Cortical bone of mandible Mandible, NOS Cartilage, NOS Cortical bone, NOS (not specified in higher codes) Bone, NOS (not specified in higher codes)	Extension Size	Extension Size	RE	RE
545	Cortical bone of maxilla Maxilla, NOS	Extension Size	Extension Size	D	D
550	Subcutaneous soft tissue of chin/neck	Extension Size	Extension Size	RE	RE
600	Epiglottis Glossoepiglottic fold Glossopharyngeal sulcus Lateral pharyngeal wall Pharyngeal (lingual) surface Pharyngoepiglottic fold Tonsillar pillars and fossae Tonsils Vallecula	Extension Size	Extension Size	RE	RE
603	600 +550	Extension Size	Extension Size	RE	RE
605	(550 or 600) + 545 Any structure in code 550 or 600 plus any structure in code 545	Extension Size	Extension Size	D	D
620	Deep (extrinsic) muscle of tongue: Genioglossus Geniohyoid Hyoglossus Mylohyoid Palatoglossus Styloglossus	T4a	T4a	L	L
630	OBSOLETE DATA RETAINED V0200 (620) + any of (500, 530, or 600)	ERROR:	T4a	RE	RE
635	620 + (500, 530, 535, 550, or 600) Any structure in code 620 plus any structure in code 500, 530, 535, or 600	T4a	T4a	RE	RE
640	OBSOLETE DATA CONVERTED V0200 Assign to T1-3 category per site curator, see code 550 Subcutaneous soft tissue of chin/neck	ERROR:	ERROR:	ERROR:	ERROR:
645	620 + 545 Any structure in code 620 plus any structure in code 545	T4a	T4a	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, 635, 725, or 765 as appropriate. Mandible	ERROR:	ERROR:	ERROR:	ERROR:
725	Trabecular bone of mandible	T4a	T4a	RE	RE
760	Skin of undersurface of chin/neck	T4a	T4a	RE	RE
765	(725 or 760) + 545 Any structure in code 725 or 760 plus any structure in code 545	T4a	T4a	D	D
770	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 545, 605, 645, 765, or 775 as appropriate Maxillary sinus	ERROR:	ERROR:	ERROR:	ERROR:
775	Trabecular bone of maxilla Maxillary sinus (antrum)	T4a	T4a	D	D
780	Stated as T4a with no other information on extension	T4a	T4a	RE	RE
788	Specified bone (Other than mandible, maxilla, or bones in codes 790 and 805)	T4b	T4b	D	D
790	Masticator space Pterygoid plates	T4b	T4b	D	D
800	OBSOLETE DATA RETAINED V0200 Further contiguous extension: Base of skull Masticator space Pterygoid plates	ERROR:	T4b	D	D
805	Further contiguous extension: Base of skull 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

- Note: For CS Extension codes 100 through 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. - Note: For CS Extension codes 100 through 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.