Objective:

Numb chin syndrome is an important clinical sign which may allow a neurologist to suspect metastatic cancer on physical examination. 

Background:

Charles Bell first reported numb chin syndrome in a patient with known breast cancer. It remains an important clinical sign for metastatic carcinoma and rheumatological disease causing mass lesions. 

Design/Methods:

Written informed consent for publication of case report and images was obtained from patient. 

Results:

Case presentation:
72-year-old female with history of newly diagnosed diabetes presented to the emergency room as a stroke code due to right peripheral facial palsy and lack of sensation to light touch and pinprick in the right mental nerve distribution. 
CT head and CT angiographic imaging of head and neck were normal from neurological perspective, but patient was found to have a 1.9 cm irregular solid left apical lung nodule and cervical lymphadenopathy along the right jugular vein, including a necrotic lymph node. MRI demonstrated 3.8 cm enhancing submandibular neck mass. Marrow enhancement and edema within the right aspect of the mandible concerning for osseous involvement of disease.

Lung node biopsy was consistent with adenoid cystic carcinoma with small, angulated cells positive for cytokeratin AE1/AE3, p40, and CD117, while being negative for TTF-1, Napsin A, chromogranin, and synaptophysin. Primary lung malignancy as well as metastasis to the lung from salivary gland are considered. 

Conclusions:

Recognition of numb chin syndrome allowed for the patient to get appropriate diagnostic tests. Possible primary right submandibular gland tumor with extension into the mandible likely pressed on the inferior alveolar nerve and its mental nerve branch. Possible parotid swelling could have caused pressure on the facial nerve.