Stage IVA includes: (T4a, N0, M0); (T4a, N1, M0); (T1, N2, M0); (T2, N2, M0); (T3, N2, M0); (T4a, N2, M0). T4a: Maxillary sinus: Moderately advanced local disease. Tumor invades anterior orbital contents, skin of cheek, pterygoid plates, infratemporal fossa, cribriform plate, sphenoid or frontal sinuses. Nasal cavity and ethmoid sinus: Moderately advanced local disease. Tumor invades any of the following: anterior orbital contents, skin of nose or cheek, minimal extension to anterior cranial fossa, pterygoid plates, sphenoid or frontal sinuses. T1: Maxillary sinus: Tumor limited to the maxillary sinus mucosa with no erosion or destruction of bone. Nasal cavity and ethmoid sinus: Tumor restricted to any one subsite, with or without bony invasion. T2: Maxillary sinus: Tumor causing bone erosion or destruction including extension into the hard palate and/or middle nasal meatus, except extension to posterior wall of maxillary sinus and pterygoid plates. Nasal cavity and ethmoid sinus: Tumor invading two subsites in a single region or extending to involve an adjacent region within the nasoethmoidal complex, with or without bony invasion. T3: Maxillary sinus: Tumor invading any of the following: bone of the posterior wall of maxillary sinus, subcutaneous tissues, floor or medial wall of orbit, pterygoid fossa, or ethmoid sinuses. Nasal cavity and ethmoid sinus: Tumor invading the medial wall or floor of the orbit, maxillary sinus, palate, or cribriform plate. N0: No regional lymph node metastasis. N1: Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension and ENE(-). N2: Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(+); or metastasis in a single ipsilateral lymph node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(-); or metastases in multiple ipsilateral lymph nodes , none larger than 6 cm in greatest dimension and ENE(-); or metastases in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-). M0: No distant metastasis. (AJCC 8th ed.) [from NCI]