Head and neck cancers
begin in squamous cells that line the moist, mucosal surfaces inside the head and neck. These kinds of cancers related to squamous cells are referred to as squamous cell carcinomas.
Cancers of head and neck are further differentiated by the area of head and neck in which they begin. This form of cancer starts in lip, oral cavity (mouth), nasal cavity, paranasal sinuses, pharynx and larynx.
Cancers in brain, eye, esophagus, thyroid gland, scalp, muscles and bones of head and neck are not categorized under head and neck cancers. In some cases, squamous cells can be found in lymph nodes of upper neck when there is no evidence of cancer in other parts of head and neck. If this happens, cancer is called metastatic squamous neck cancer with unknown (occult) primary.