[Mandibular neuropathy due to infiltration of the Gasser ganglion]

The numb chin syndrome is characterized by oral and facial numbness restricted to the distribution of the mental nerve. This uncommon neuropathy has been described in association with a number conditions including malignant disease even in the patients no known to have cancer. Numb chin syndrome may be caused by metastatic involvement of the mental nerve, by involvement of the proximal mandibular root at the base of the skull or by intracranial leptomeningeal spread.

We described a case of neuropathy of the chin as the initial symptom of the breast cancer. We suggested that the lesion was in the trigeminal ganglion based on enlargement and gadolinium enhancement of the trigeminal ganglia on MRI. A mental neuropathy should initiate a search for cancer that includes MRI of the head.