Head and Neck: Spaces, Nodes, and Mucosal Patterns
Core concepts
Anchor head and neck questions in the fascial spaces (parapharyngeal, masticator, submandibular, parotid, retropharyngeal, perivertebral) and their contents. Know the lymph node levels I–VI and the imaging criteria for pathologic nodes (size, necrosis, extranodal extension, loss of fatty hilum). For mucosal lesions, separate squamous cell carcinoma (enhancing, invasive, nodal spread) from benign patterns. Understand the parotid (superficial vs. deep lobe, facial nerve plane) and the thyroid (TIRADS features: composition, echogenicity, shape, margins, echogenic foci). Recognize classic entities: juvenile nasopharyngeal angiofibroma (adolescent male, avid enhancement, spares nasopharynx), pleomorphic adenoma (well-defined, T2 bright), and Warthin tumor (bilateral, cystic).
Traps
Questions test perineural spread (V2/V3, facial nerve) as a subtle cause of treatment failure, extranodal extension as a staging upgrader, and retropharyngeal vs. prevertebral involvement. A common trap is confusing a branchial cleft cyst with a necrotic node, or calling a thyroglossal duct cyst a nodal mass.
Worked rule of thumb
For any head and neck mass, trace the nerve and space: a lesion along V3 or the facial nerve canal should prompt a search for perineural spread. For nodes, size alone is insufficient-call necrosis or extranodal extension when present, as these change management.