Oral and Maxillofacial Surgical Pathology
Core Concepts
Surgical pathology of the head and neck requires a systematic approach: describe the specimen, orient it, sample margins, and correlate with imaging. Know the classic histologic features of squamous cell carcinoma variants (verrucous, spindle cell, basaloid, papillary), the distinction between dysplasia grades, and the significance of depth of invasion and worst pattern of invasion. Understand reactive vs neoplastic lesions: pyogenic granuloma, peripheral giant cell granuloma, traumatic fibroma, and granular cell tumor.
Common Traps
- Confusing verrucous carcinoma (broad pushing rete, minimal atypia, no conventional invasion) with well-differentiated SCC.
- Overdiagnosing pseudoepitheliomatous hyperplasia over granular cell tumors or inflammatory lesions as carcinoma.
- Misinterpreting necrotizing sialometaplasia as SCC or mucoepidermoid carcinoma.
- Forgetting that margin status depends on specimen orientation and that close margins (<5 mm) may be reported separately.
Rule of Thumb
For any mucosal mass, ask three questions in order: (1) Is it surface epithelial, salivary, mesenchymal, or lymphoid? (2) Is the process reactive or neoplastic? (3) If neoplastic, is it benign or malignant, and what is the margin distance? A worked example: a firm palatal mass with surface ulceration and pseudoepitheliomatous hyperplasia over sheets of granular cells - the atypia is reactive, and the diagnosis is granular cell tumor, not SCC. Always request immunohistochemistry (S100 positive) when the differential includes both.
Documentation
Record size in three dimensions, anatomic site, mucosal vs deep margin, perineural or lymphovascular invasion, and bone involvement. These drive staging and adjuvant therapy decisions.