Oral Pathology and Oral Medicine
Approach
Use a systematic scheme for every lesion: site, size, colour, surface, consistency, duration, associated symptoms, and systemic context. Learn the classic ulcer differential (recurrent aphthous, traumatic, herpes, squamous cell carcinoma, drug-related, haematological) and the classic white patch differential (frictional keratosis, leukoplakia, candidiasis, lichen planus, nicotine stomatitis, squamous cell carcinoma). Know the red patch rule: erythroplakia is rarer than leukoplakia but has a higher malignant transformation rate. Know oral potentially malignant disorders and the concept of dysplasia grading.
Know the vesiculobullous diseases: pemphigus vulgaris (intraepithelial, desmoglein 3, positive Nikolsky, suprabasal cleft), mucous membrane pemphigoid (subepithelial, linear IgG/C3 at basement membrane), erythema multiforme, and the drug-induced mimics. Know lichen planus (Wickham striae, band-like lymphocytic infiltrate, saw-tooth rete ridges) versus lichenoid drug reaction. Know candidiasis variants, herpes simplex and varicella-zoster presentations, and salivary gland pathology (mucocele, ranula, pleomorphic adenoma, adenoid cystic carcinoma with perineural invasion). Know fibro-osseous lesions, giant cell lesions, odontogenic cysts and tumours (ameloblastoma, odontoma, keratocyst), and the lymphoma red flags (B symptoms, persistent lymphadenopathy, unexplained bleeding).
Oral medicine interface
Be fluent in burning mouth, xerostomia, halitosis, taste disturbance, oral manifestations of systemic disease (diabetes, anaemia, HIV, Crohn's, Sjögren's, syphilis), and adverse drug reactions. Recognise oral cancer red flags: non-healing ulcer >2 weeks, induration, fixation, lymphadenopathy, unilateral symptoms.
Traps
- Pemphigus = intraepithelial (suprabasal); pemphigoid = subepithelial.
- Leukoplakia is a clinical diagnosis of exclusion, not a histological one.
- A negative biopsy does not exclude malignancy if the clinical picture is suspicious - re-biopsy.
Rule of thumb
Any oral ulcer persisting beyond two weeks without a clear cause should be referred for biopsy or specialist assessment.