CS Extension

Notes

**Note 1**: Superficial erosion alone of bone/tooth socket by gingival primary is not sufficient to code as bone involvement (code 700). **Note 2**: Periosteum is a fibrous membrane that wraps the outer surface of bones. Mucoperiosteum is a compound structure of mucous membrane and periosteum. 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 3**: AJCC assigns the T category based on size for involvement of cortical bone. Involvement through cortical bone is required for assignment of T4a. **Note 4**: 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, 775, 810, or 815 as appropriate to code CS Extension based on a statement of T when no other extension information is available. **Note 5**: Use code 300 for localized tumor only if no information is available to assign code 100, 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 (mucoperiosteum) (stroma) 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)
Labial mucosa (inner lip), lip
Tongue (mucosa)
Extension Size Extension Size RE RE
535 Cartilage of mandible or maxilla
Cortical bone of mandible or maxilla
Mandible, NOS
Maxilla, NOS
Cartilage, NOS
Cortical bone, NOS
Bone, NOS
Extension Size Extension Size RE RE
550 Facial muscle, NOS
Subcutaneous soft tissue of face
Extension Size Extension Size RE RE
600 Lateral pharyngeal wall
Tonsillar pillars and fossae
Tonsils
Extension Size Extension Size RE RE
650 Soft palate including uvula Extension Size Extension Size RE RE
720 Deep (extrinsic) muscle of tongue:
Genioglossus
Hyoglossus
Palatoglossus
Styloglossus
T4a T4a RE RE
725 Trabecular bone:
Mandible
Maxilla
Palatine bone
T4a T4a RE RE
760 Skin of face T4a T4a D D
770 Maxillary sinus (antrum) T4a T4a D D
775 Stated as T4a with no other information on extension T4a T4a RE RE
788 Specified bone
(Other than maxilla, mandible, or bones in codes 795 and 805)
T4b T4b D D
790 OBSOLETE DATA CONVERTED V0200
See code 805

Skull
ERROR: ERROR: ERROR: ERROR:
795 Masticator space
Pterygoid plates
T4b T4b D D
800 OBSOLETE DATA RETAINED V0200

Further contiguous extension, including:
Masticator space
Pterygoid Plates
Skull base
Encases internal carotid artery
ERROR: T4b D D
805 Further contiguous extension including:
Base of skull
Internal carotid artery (encased)
Skull
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 100-650 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 100-650 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.