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.