Table 1. The T-staging system proposed for sinonasal B-cell lymphoma.

Stage	Definition
T1	Confinement to the nasal cavity.
T2	Extension to the maxillary sinus, anterior ethmoid sinus, or hard palate.
T3	Extension to posterior ethmoid sinus, sphenoidal sinus, orbit, superior alveolar bone, cheeks, or superior buccinators space.
T4	Involvement of the inferior alveolar bone, inferior buccinators space, infratemporal fossa, nasopharynx, or cranial fossa.