Head and Neck Surgery
Core concepts
Work from anatomical levels of the neck (I–VI) and the lymphatic drainage of each subsite: oral cavity to levels I–III, oropharynx to II–IV, nasopharynx to retropharyngeal and V, thyroid to VI. Know the AJCC TNM principles - particularly that extranodal extension upstages to N3b and that HPV-positive oropharyngeal cancer has a separate staging system. Understand the parotid facial nerve plane (superficial vs deep lobe) and the recurrent laryngeal nerve relationship to the inferior thyroid artery. Be able to describe the work-up of a neck lump: FNA cytology, ultrasound, and panendoscopy with PET-CT when indicated.
Traps
The classic trap is the "branchial cyst" in a patient over 40 - always exclude a cystic metastasis from a Waldeyer's ring primary. Another is misdiagnosing laryngeal cancer staging: impaired mobility is T2, fixation is T3, and pre-epiglottic/paraglottic space invasion changes T stage. Remember follicular thyroid carcinoma cannot be diagnosed on FNA - capsular invasion requires histology. Also know that level IIa vs IIb matters for spinal accessory nerve preservation.
Worked example / rule of thumb
A 55-year-old with a painless level II neck mass and normal examination: proceed to FNA, ultrasound-guided, then PET-CT and panendoscopy with tonsillectomy and base-of-tongue biopsy to find a primary. Rule of thumb: "A cystic level II mass in an adult is a metastasis until proven otherwise."