EOD Primary Tumor


**Note 1:** Involvement of the pharyngeal space (code 300) is defined as posterolateral infiltration from the nasopharynx beyond the buccopharyngeal fascia into the triangular space lateral to the pharynx. **Note 2:** Parapharyngeal involvement denotes posterolateral infiltration of tumor beyond the pharyngobasilar fascia. The pharyngobasilar fascia is the fibrous layer of the pharyngeal wall between the mucosa and the muscular layer, attached superiorly to the basilar part of the occipital bone and diminishing in thickness as it descends. **Note 3:** The masticator space primarily consists of the muscles of mastication, the medial and lateral pterygoid, masseter, and temporalis muscles. The space also includes the ramus of the mandible and the third division of cranial nerve V as it passes through the foramen ovale into the suprahyoid neck.
Code Description SS2018 T
000 In situ, intraepithelial, noninvasive IS
100 Invasive tumor confined to one of the following subsites - Inferior wall (superior surface of soft palate) - Lateral wall - Posterior superior wall (vault) Involvement of two or more subsites - Lateral wall extending into eustachian tube/middle ear - Posterior, inferior, or lateral wall(s) Confined to nasopharynx, NOS Localized, NOS L
200 Nasal cavity WITHOUT pharyngeal extension Oropharynx Soft palate, inferior surface including uvula WITHOUT pharyngeal extension Soft tissue, NOS (excluding soft tissue of neck) RE
300 Any site listed in codes 100 or 200 - WITH fixation or tumor described only as FIXED with parapharyngeal extension Adjacent soft tissue involvement Lateral pterygoid Medial pterygoid Parapharyngeal space Prevertebral muscles Pterygopalatine fossa WITHOUT bone invasion RE
500 Bone, NOS Bony structures of skull base Cartilage, NOS Cervical vertebra Floor of orbit Hard palate Paranasal sinuses Pterygoid structures Skull base RE
700 Brain Cranial nerve involvement Hypopharynx Infratemporal fossa/masticator space Intracranial extension, NOS Orbit except bone of floor of orbit Parotid gland Soft tissues of neck D
800 No evidence of primary tumor No tumor identified, but EBV-positive cervical node(s) involvement U
999 Unknown; extension not stated Primary tumor cannot be assessed Not documented in patient record Death Certificate Only U
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