["Numb chin syndrome": first presenting syndrome of multiple sclerosis?]

HISTORY AND CLINICAL FINDINGS: A 34-year-old previously healthy woman presented with a five-day history of subacute onset of a numb chin. Examination on admission revealed isolated hypesthesia on the left side of the chin and lower lip. INVESTIGATIONS: Brain magnetic resonance imaging (MRI) demonstrated a lesion involving the pontine trigeminal fibers and multiple periventricular T2-hyperintense white matter lesions suggestive of inflammatory /demyelinating disease. Cerebrospinal fluid analysis revealed oligoclonal IgG bands (only in cerebrospinal fluid) and an increased IgG index. A follow-up MRI after four months demonstrated new supratentorial brain lesions, confirming a syndrome, highly suggestive of multiple sclerosis as the likely underlying diagnosis. TREATMENT AND FOLLOW-UP: The facial sensory disturbance resolved spontaneously. Prophylactic treatment with interferon-beta was started. CONCLUSION: The numb chin syndrome may be the initial presentation of a clinically isolated syndrome suggestive of multiple sclerosis. Prophylactic immunomodulatory treatment may be started after the suspicion of inflammatory/demyelinating activity is confirmed.