Numb chin syndrome- The first finding in metastatic malignancy

Abstract

Numb chin syndrome (NCS) is a sensory neuropathy of the mental nerve, which is accompanied by hypoesthesia and paresthesia of the jaw and lower lip. Although being well known in neurology practice, most of the physicians who have not experienced this phenomenon are unaware of this phenomenon since it is rare and can be confused with somatic complaints. This case report aims to point out that NCS may be the first sign and symptom of metastatic cancers in patients who are not diagnosed. We report a 52-year-old man who presented to our outpatient clinic with numbness on his right jaw for 1 month. He had a history of renal transplantation and used immunosuppressive therapy. He was diagnosed as metastatic lung cancer when he was investigating the etiology and died within a month. Patients presenting with numb chin syndrome are diagnosed late because of being rare. 75% of the patients presenting with this complaint are due to malignant metastasis and maybe the first sign of malignancy in a significant rate of them, as presented here. Many malignant and metastatic neoplasms may cause this neuropathy. In most cases, life expectancy is short and is considered as a sign of poor prognosis. Numb chin syndrome is a lesser known symptom of mental nerve neuropathy. In case dental and jaw-related pathologies cannot be detected, it should be kept in mind that this may be the first sign of malignancy and all detailed investigations should be planned for this purpose.