Oral medicine, oral pathology and radiology
Red flags and pattern recognition
Oral medicine questions are built around history and red flags. Any ulcer persisting beyond three weeks, a single ulcer that is indurated, fixed to deep tissues, or associated with lymphadenopathy or unexplained bleeding must be treated as suspected malignancy and referred urgently for biopsy. Know recurrent aphthous stomatitis and its variants, traumatic ulceration, and the potentially malignant disorders: leukoplakia and erythroplakia are clinical diagnoses requiring biopsy, whereas lichen planus has characteristic bilateral reticular striae, and oral submucous fibrosis presents with progressive trismus and blanching.
Distinguish vesiculobullous disease: pemphigus vulgaris gives fragile intraoral bullae, positive Nikolsky sign and intercellular IgG on immunofluorescence; mucous membrane pemphigoid gives intact blood-stained blisters, gingival desquamation and a linear basement-membrane pattern. Salivary disease (Sjögren syndrome, obstructive sialadenitis, mucocele), candidiasis variants, trigeminal neuralgia and Bell's palsy also appear.
Radiology asks you to describe before diagnosing. Learn the classic patterns: ground-glass opacity in fibrous dysplasia, sun-ray periosteal reaction in osteosarcoma, soap-bubble multilocular radiolucency in ameloblastoma, scalloped multilocular radiolucency at the posterior mandible angle in odontogenic keratocyst, a pericoronal radiolucency in dentigerous cyst, and the periapical granuloma versus radicular cyst distinction, which is histological rather than radiographic. Apply ALARA, justification and collimation; a lead thyroid collar is standard.
Worked example: a 58-year-old with a 6-week non-healing lateral tongue ulcer and a firm submandibular node scores two red flags (duration, induration) - urgent two-week referral, not a review appointment.
Traps: diagnosing leukoplakia histologically (it is clinical), and misreading 'well-defined' as benign.