Oral Pathology and Oral Medicine
What this domain tests
This domain tests diagnosis and management of mucosal, salivary, osseous, and systemic conditions affecting the mouth. Items often present a lesion description and ask for the next step, the most likely diagnosis, or the feature that distinguishes benign from malignant disease.
Core rules and concepts
- Leukoplakia is a clinical diagnosis for a white patch that cannot be characterized as another disease. Erythroplakia carries a higher malignant transformation risk than most homogeneous leukoplakias.
- Oral lichen planus often shows reticular Wickham striae, sometimes erosive areas. It is immune-mediated and has a small malignant transformation risk, so monitoring is needed.
- Pseudomembranous candidiasis wipes off, leaving erythema. Erythematous candidiasis and angular cheilitis are common in denture wearers, dry mouth, diabetes, and inhaled steroid use.
- Recurrent aphthous ulcers are painful, recurrent, and non-keratinized-site lesions. Herpes lesions begin as coalescing vesicles with prodromal tingling.
- Squamous cell carcinoma risk factors include tobacco, alcohol, betel quid, and HPV 16 in the oropharynx. A nonhealing ulcer over two weeks, induration, fixity, or unexplained bleeding needs biopsy.
- Odontogenic cysts include radicular, dentigerous, and keratocystic lesions. Ameloblastoma is a locally aggressive odontogenic tumor, often in the posterior mandible.
- Sjögren syndrome causes xerostomia, keratoconjunctivitis sicca, and anti-Ro or anti-La antibodies.
Worked example
A 60-year-old smoker has a 6-week nonhealing ulcer on the lateral tongue. The reasoning is that duration beyond two weeks, induration, and fixation raise concern for squamous cell carcinoma. Do not treat empirically with antifungal or steroid therapy and wait. Refer for biopsy and imaging; early diagnosis improves outcomes.
Traps that cost marks
Do not call every white patch leukoplakia after biopsy; leukoplakia is clinical. Erythroplakia is not simple inflammation. Not every radiolucency is a cyst. Avoid biopsy of a vascular lesion without imaging. Also remember that oral lichen planus is a clinical-pathologic diagnosis and needs monitoring rather than reassurance alone.