Numb chin syndrome as a manifestation of metastatic squamous cell carcinoma of esophagus

Numb chin syndrome (NCS) is a sensory neuropathy presenting with numbness of the chin in the distribution of the mental nerve and the branches of the mandibular division of the trigeminal nerve. Though it can be caused by a benign process, NCS should be regarded as being due to malignancy until proven otherwise. Among the malignancies that cause NCS the most common are breast cancer, prostate cancer, and lymphoreticular malignancy. In squamous cell carcinoma (SCC) of the esophagus, spread to the mandible is a rare and often late event. An often overlooked clinical sign in mandibular metastases is hypoesthesia or paresthesia over the peripheral distribution of the inferior alveolar nerve/mental nerve; this sign has been referred to in the literature as NCS or numb lip syndrome or mental nerve neuropathy. Rarely, this may be the first presentation of a disseminated malignancy. Prognosis is usually poor. The discovery of this symptom should alert the clinician to the possibility of disseminated disease. In this article we report a rare case of metastatic SCC of the esophagus in a 40-year-old male patient who presented with NCS. We also review the mechanism, causes, and evaluation of NCS.