Level V is the area of lymph nodes in the cervical neck. There are VII levels, level I though VII in the lymph chain in the cervical neck, with over 300 lymph nodes, mostly microscopic, and each area certain H&N cancers travel to first, and can be a clue where the primary is at diagnosis. For example, oropharynx cancer usually goes to level II first, Oral cancer to level I, but there can be skip metastases, and further involvement. The further down the chain cancer goes, can be more difficult to treat.

Stage IV cancer also has, a, b and c depending the number of lymph nodes, size, and involvement to distant area, and other structures.

Level IV aso has dares close to the collar bone.

They can do a FNAB, under ultrasound guidance, to see if its cancerous or not, and other pathology.

Good luck.