Table 1:

TNM staging of sinonasal malignancies as per AJCC 8^th edition

TNM Staging	Nasal cavity/Ethmoid Sinus	Maxillary Sinus
T-stage
Tis	Carcinoma in situ
T1	tumor limited to one subsite (septum, floor, lateral wall, or vestibule (edge of naris to mucocutaneous junction of nasal cavity); left or right ethmoid sinus)	tumor limited to maxillary sinus mucosa (no bone erosion/destruction)
T2	tumor involving two subsites in one region or extending to involve an adjacent region in the nasoethmoidal complex	tumor with bone erosion/destruction, including extension into hard palate and/or middle meatus, excluding structures in a higher T category
T3	Tumor invades any of the following:  • medial wall or floor of orbit  • maxillary sinus  • palate  • cribriform plate	Tumor invades any of the following:  • bone of posterior wall of maxillary sinus  • subcutaneous tissues  • floor or medial wall of orbit  • pterygoid fossa  • ethmoid sinuses
T4a	Tumor invades any of the following:  • anterior orbital contents  • skin of nose or cheek  • minimal extension to anterior cranial fossa  • pterygoid plates  • Sphenoid sinus  • Frontal sinus	Tumor invades any of the following:  • anterior orbital contents  • skin of cheek  • pterygoid plates  • infratemporal fossa  • cribriform plate  • sphenoid sinus  • frontal sinus
T4b	Tumor invades any of the following:  • orbital apex  • middle cranial fossa  • dura  • brain  • cranial nerves other than maxillary division of trigeminal nerve (V2)  • nasopharynx  • clivus
N-stage
N0	no regional node metastases
N1	metastasis in single ipsilateral node, ≤3 cm, and no extranodal extension (ENE(−))
N2a	metastasis in single ipsilateral node, >3 cm and ≤6 cm, and ENE(−); or metastasis in single ipsilateral node, ≤3 cm, and ENE(+)
N2b	metastasis in multiple ipsilateral nodes, all ≤6 cm, and ENE(−)
N2c	metastasis in bilateral or contralateral nodes, all ≤6 cm, and ENE(−)
N3a	metastasis in a node, >6 cm, and ENE(−)
N3b	metastasis in single ipsilateral node, >3 cm, and ENE(+); or multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+); or single contralateral node of any size and ENE(+)