Oral Medicine, Oral Pathology and Oral Radiology
What the exam tests
This domain tests recognition of oral mucosal disease, red flags for malignancy, biopsy principles and radiographic differential diagnosis. The exam expects you to know when to observe, when to biopsy and when to refer urgently.
Core rules and concepts
- Ulcers: recurrent aphthous ulcers heal within about two weeks; herpes lesions are clustered and prodromal. Any ulcer persisting beyond two to three weeks, especially on the lateral tongue or floor of mouth, needs biopsy to exclude squamous cell carcinoma.
- Potentially malignant disorders: leukoplakia is a diagnosis of exclusion; erythroplakia has a higher malignant transformation risk; oral submucous fibrosis and lichen planus need long-term review.
- Vesiculobullous disease: pemphigus vulgaris and mucous membrane pemphigoid require incisional biopsy for histology and direct immunofluorescence; do not treat blindly with steroids.
- Salivary disease: Sjögren syndrome causes dry mouth and salivary gland enlargement; mucocele is common on the lower lip.
- Radiology: describe lesions as radiolucent or radiopaque, well or ill defined, and relate them to teeth. Odontogenic keratocyst and ameloblastoma are important differentials for jaw radiolucencies.
Worked example
A 60-year-old smoker has a 2 cm ulcer on the lateral tongue that has persisted for six weeks with induration. Reasoning: the duration, site and induration are red flags. Do not prescribe a steroid rinse; arrange urgent biopsy or referral to oral and maxillofacial surgery, and document tobacco and alcohol exposure.
Traps
Treating a non-healing ulcer with steroids before diagnosis; missing erythroplakia because it is asymptomatic; assuming every radiolucency is a cyst; failing to perform direct immunofluorescence in vesiculobullous disease; not recording the size and site of a lesion.