Chapter 16: Head and Neck Pathology

Head and Neck Pathology exploration of head and neck pathology details a diverse spectrum of clinical conditions affecting the oral cavity, upper respiratory tract, ears, and salivary glands. It begins by examining the oral microbiome and the pathogenesis of common dental diseases, such as dental caries caused by bacterial acid production and inflammatory conditions like gingivitis and periodontitis, which can lead to permanent tooth loss and systemic health complications. The text analyzes various reactive and infectious oral lesions, including painful aphthous ulcers, fibrous proliferations like pyogenic granulomas, and fungal infections such as oral candidiasis (thrush). A significant emphasis is placed on the identification of precancerous leukoplakia and erythroplakia, emphasizing their potential progression into squamous cell carcinoma (SCC). The chapter highlights a critical shift in oncology, contrasting "classic" SCC driven by tobacco and alcohol with the rising incidence of oropharyngeal SCC associated with high-risk human papillomavirus (HPV) infection, noting differences in their molecular driver mutations and clinical outcomes. Further sections detail odontogenic cysts and tumors, such as the aggressive ameloblastoma, and upper airway disorders including allergic rhinitis, sinusitis, and nasopharyngeal carcinoma linked to the Epstein-Barr virus (EBV). The discussion extends to laryngeal pathology, highlighting the impact of vocal cord nodules and laryngeal cancer on voice quality, and covers ear disorders like otitis media and otosclerosis. Finally, the summary reviews neck-specific lesions like branchial cleft cysts and paragangliomas alongside a thorough classification of salivary gland neoplasms, ranging from the benign pleomorphic adenoma and Warthin tumor to the malignant mucoepidermoid carcinoma.