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 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, 778, 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 codes 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:
Labial mucosa (inner lip)
Lamina propria
Multiple foci
Submucosa (superficial invasion)
Vermilion surface
Superficial extension to:
Skin of lip
Subcutaneous soft tissue of lip
Extension Size Extension Size L L
200 Musculature 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 Buccal mucosa (inner cheek)
Commissure
Opposite lip (both lips)
Extension Size Extension Size RE RE
510 OBSOLETE DATA REVIEWED AND CHANGED V0203
Code 510 defined as "Gingiva" in CSv1. Code 510 defined as "Upper gingiva, Gingiva, NOS" in CSv2:V0201, V0202. All cases should be reviewed and recoded to 515, 780, or 785 as appropriate.

Upper gingiva
Gingiva, NOS
ERROR: ERROR: ERROR: ERROR:
515 Upper gingiva
Gingiva, NOS
Extension Size Extension Size RE RE
535 Cortical bone of maxilla
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.

Maxilla
ERROR: ERROR: ERROR: ERROR:
725 Trabecular bone of maxilla T4a T4a RE RE
740 Nose T4a T4a RE D
750 Tongue T4a T4a D D
760 Skin of face/neck 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 775, 785, or 788 as appropriate.

Cortical bone (other than code 700)
Floor of mouth
Inferior alveolar nerve
ERROR: ERROR: ERROR: ERROR:
775 Floor of mouth
Inferior alveolar nerve
T4a T4a D D
778 Stated as T4a with no other information on extension T4a T4a RE RE
780 Lower gingiva T4b T4b D RE
785 780 + (740, 750, 760, or 775)

Lower gingiva plus any structure in codes 740, 750, 760, or 775
T4b T4b D D
788 Bone of mandible
Mandible, NOS
Specified bone
(Other than maxilla and bones in codes 790 and 800)
T4b T4b D D
790 Masticator space
Pterygoid plates
T4b T4b D D
800 Further contiguous extension including:
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 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.