Table 2.

The Dulguerov staging system for olfactory neuroblastoma

Staging	Description
Primary tumor
T1	Tumor involving the nasal cavity and/or paranasal sinuses (excluding sphenoid), sparing the most superior ethmoid
T2	Tumor involving the nasal cavity and/or paranasal sinuses (including the sphenoid) with extension to or erosion of the cribriform plate
T3	Tumor extending into the orbit or protruding into the anterior cranial fossa, without dural involvement
T4	Tumor involving the brain
Lymph nodes
N0	No cervical lymph node metastasis
N1	Any form of cervical lymph node metastasis
Distant metastasis
M0	No metastases
M1	Distant metastases