Oral Pathology and Oral Medicine
What this domain tests
This domain tests the distinction between reactive, immune-mediated, infective and neoplastic lesions; recognition of red flags; and selection of the correct investigation. Oral medicine also covers mucosal disease, salivary disorders, facial pain and systemic associations.
Core rules
- Leukoplakia is a clinical diagnosis of exclusion: a predominantly white patch that cannot be characterised as any other lesion. Biopsy is required to exclude dysplasia or carcinoma.
- Erythroplakia is red, velvety and carries a high risk of dysplasia or carcinoma; biopsy urgently.
- Oral squamous cell carcinoma risk factors include tobacco, betel/paan, alcohol and HPV (especially oropharyngeal). Persistent ulcer over 2 weeks, induration, fixation and lymphadenopathy are red flags.
- Recurrent aphthous stomatitis causes painful, recurrent, non-indurated ulcers with a yellow fibrin centre and erythematous halo; biopsy is reserved for atypical disease.
- Pseudomembranous candidiasis wipes off to leave erythema; consider diabetes, inhaled steroids, HIV and xerostomia.
- Oral lichen planus typically shows bilateral reticular white striae (Wickham); erosive forms need biopsy.
- Pemphigus vulgaris is intraepithelial (flaccid bullae, positive Nikolsky); pemphigoid is subepithelial (tense blisters, anti-BP180/230).
- Radicular cysts occur at the apex of a non-vital tooth; dentigerous cysts surround the crown of an impacted tooth; ameloblastoma is locally aggressive.
Worked example
A 55-year-old smoker has a 3-cm indurated ulcer on the lateral tongue present for 6 weeks, fixed to deep tissues, with a hard submandibular node. This is not a traumatic ulcer. The correct step is urgent referral for biopsy and imaging, not a 2-week review or antifungal trial. Duration, induration, fixation and lymphadenopathy force action.
Traps
- Do not diagnose leukoplakia after rubbing off a white plaque; if it wipes off, think candidiasis.
- Traumatic ulcers should heal after cause removal; persistence demands biopsy.
- Normal-looking mucosa does not exclude dysplasia.
- Do not treat erosive lichen planus with antifungals alone.