Limited to the mucosa and immediately underlying soft tissue
irrespective of thickness or greatest dimension
T4
Moderately or highly advanced
T4a
Involving deep soft tissue ,cartilage ,bone ,or
overlying skin
T4b
Involving brain, dura ,skull base ,lower cranial
nerves (IX, X , XI, XII ),masticator space ,carotid artery ,prevertebral
space , or mediastinal structure