FIGURE 1.

Head and neck cancer (HNC) classification and different anatomical sites involved. (A) HNC can be broadly classified on the basis of its anatomical site, histological origin, and etiological factors. Upon histological evaluation, tumors in the head and neck region can be broadly classified into malignant and premalignant lesions. Premalignant lesions that have been indicated here are not cancer but are precursors of malignant lesions. (B) Detailed anatomical architecture of the head and neck region illustrating the location of the oral cavity, nasal cavity, tongue, salivary glands (sublingual gland, submaxillary gland, and parotid gland), larynx and pharynx (including oropharynx, nasopharynx, and hypopharynx), and site of primary tumors.