Cancers of the head and neck are composed of a spectrum of malignant neoplasms. Most commonly, however, "head and neck cancer" refers to epithelial carcinomas, squamous cell cancers, and their variant histologic subtypes that arise from the mucosal surfaces of the upper aerodigestive tract and constitute over 85% of the cancers encountered in this region. Those caring for patients with head and neck neoplasms must be conversant with the variable natural histories and approaches to treatment for the many different malignant tumors that arise within this region.
Cancers of the head and neck are traditionally divided into nine distinct anatomic regions from which mucosal cancers originate (Table 68-1). Other neoplastic conditions can arise within these regions and associated areas, such as the base of skull, orbit, and neck itself, including primary tumors of the major or minor salivary glands, the skin, the thyroid or parathyroid glands, and nonepithelial tissues of the neck. Sarcomas and hematologic malignancies are also encountered in the head and neck region. Representative histopathologies encountered in clinical practice are recorded in Table 68-2. This chapter will focus on the most common cancer of the region, namely squamous cell carcinoma of the head and neck (SCCHN).
TABLE 68-1HEAD AND NECK PRIMARY SITES ||Download (.pdf) TABLE 68-1 HEAD AND NECK PRIMARY SITES
|Oral cavity ||Mobile tongue to circumvallate papillae, floor of mouth, alveolar ridge, hard palate, and buccal mucosa |
|Pharynx (3 subsites) |
| Nasopharynx ||From base of skull to dorsum of soft palate, to choanae of nasal cavities, laterally extending to Eustachian tubes |
| Oropharynx ||From the palatine arches to posterior pharyngeal wall, including soft palate, uvula, and base of tongue, extending inferiorly to larynx |
| Hypopharynx ||Pharyngeal walls posterior and lateral to larynx, including pyriform sinuses |
|Larynx (3 subsites) |
| Supraglottis ||Laryngeal structures above true vocal cords, including epiglottis, arytenoids, aryepiglottic folds, false cords, and laryngeal vestibules |
| Glottis ||Restricted to true vocal cords |
| Subglottis ||Larynx below true vocal cords, extending inferiorly 5 mm to cricoid cartilage |
|Nasal cavity ||Nasal vestibule, nasal septum, nasal turbinates, extending to maxillary wall laterally and hard palate inferiorly |
|Paranasal sinuses ||Frontal, sphenoid, ethmoid, and maxillary sinuses |
TABLE 68-2HEAD AND NECK NEOPLASMS ||Download (.pdf) TABLE 68-2 HEAD AND NECK NEOPLASMS
Squamous cell carcinoma arising in the oral cavity, oropharynx, larynx, hypopharynx, nasopharynx, and sinonasal region.
Oropharyngeal squamous cell carcinomas are frequently associated with HPV.
Nasopharyngeal carcinomas are frequently associated with EBV. WHO type I are well-differentiated, and less often EBV-associated. WHO type II are moderately differentiated. WHO type III are undifferentiated.
Premalignant lesions, characterized by dysplasia that may be mild, moderate, or severe, or carcinoma in situ.
Squamous papillomas and other verrucous lesions