Table 1. Definitions of TNM for ocular adnexal lymphoma, AJCC Cancer Staging Manual, eighth edition.

Primary tumour (T)
TX	Lymphoma extent not specified
T0	No evidence of lymphoma
T1	Lymphoma involving the conjunctiva alone without eyelid or orbital
T2	Lymphoma with orbital involvement with or without conjunctival involvement
T3	Lymphoma with preseptal eyelid involvement with or without orbital involvement and with or without conjunctival involvement
T4	Orbital adnexal lymphoma and extraorbital lymphoma extending beyond the orbit to adjacent structures, such as bone, maxillofacial sinuses and brain.
Regional lymph nodes (N)
NX	Involvement of lymph nodes not assessed
N0	No evidence of lymph node involvement
N1	Involvement of lymph node region or regions draining the ocular adnexal structures and superior to the mediastinum (periauricular, parotid, submandibular and cervical nodes)
N1a	Involvement of a single lymph node region superior to the mediastinum
N1b	Metastasis in a single ipsilateral regional lymph node based on lymph node biopsy
N2	Metastasis in a single ipsilateral regional lymph node, >3 cm in greatest dimension, or in bilateral or contralateral lymph nodes
N3	Diffuse or disseminated involvement of peripheral and central lymph node regions
Distant metastasis (M)
M0	No evidence of involvement of other extranodal sites
M1a	Noncontiguous involvement of tissues or organs external to the ocular adnexa (eg, parotid glands, submandibular gland, lung, liver, spleen, kidney, breast)
M1b	Lymphomatous involvement of the bone marrow
M1c	Both M1a and M1b involvement

AJCCAmerican Joint Committee on Cancer