A pitfall of brain MRI in evaluation of numb chin syndrome: mandibular MRI should be included to localize lesions

Numb chin syndrome: What all oral health care professionals should know

BACKGROUND

Numb chin syndrome (NCS) is a rare sensory neuropathy involving the mental nerve. Symptoms of NCS are often overlooked because of their apparent innocent nature; however, owing to the frequent association of NCS with malignancies, the opposite should be the rule. Oral health care professionals may be the first to encounter patients with NCS and should be aware of its clinical characteristics in an effort to decrease patient morbidity and mortality.

TYPES OF STUDIES REVIEWED

A search in PubMed (MEDLINE) and the Cochrane Library was performed using the terms numb chin syndrome, numb chin, mental neuropathy, mental nerve neuropathy, and malignant mental nerve neuropathy, yielding 2,374 studies. After inclusion and exclusion criteria were applied, 102 studies remained. Descriptive statistics were performed, analyzing the etiology responsible for NCS, characteristics of NCS including associated symptoms, unilateral or bilateral nature, and information on professionals visited and examinations requested to make a diagnosis.

RESULTS

NCS was associated with malignancy in 29% through 53% of the published cases. Twenty-eight percent of patients initially consulted an oral health care professional with the symptom of a numb chin. Patients more likely to have NCS were those from the ages of 61 through 70 years; 74% were unilateral; and the most common symptoms reported were numbness (100%), paresthesia (18%), and pain (17%). Forty-seven percent of the NCS cases were associated with a recurrent malignancy, and the most prevalent associated diagnoses were breast cancer (32%) and lymphoma and leukemia (24%).

CONCLUSIONS

Oral health care professionals should be aware of the characteristics of NCS as they may be the first health care providers consulted for these symptoms.

PRACTICAL IMPLICATIONS

A thorough medical and dental history as well as a complete cranial nerve screening should be performed on all patients, especially those with numbness, as this may prevent misdiagnosis and allow a timely referral and a substantial improvement of treatment course and prognosis.

Numb Chin Syndrome in Sickle Cell Disease: A Systematic Review and Recommendations for Investigation and Management

Numb chin syndrome (NCS) is a rare sensory neuropathy resulting from inferior alveolar or mental nerve injury. It manifests as hypoesthesia, paraesthesia, or, rarely, as pain in the chin and lower lip. Several case reports suggest that sickle cell disease (SCD) could be a cause of NCS. However, information about NCS is scarce in this population. Our objectives were to synthesize all the available literature relevant to NCS in SCD and to propose recommendations for diagnosis and management based on the best available evidence. A systematic review was performed on several databases to identify all relevant publications on NCS in adults and children with SCD. We identified 73 publications; fourteen reports met the inclusion/exclusion criteria. These described 33 unique patients. Most episodes of NCS occurred in the context of typical veno-occlusive crises that involved the mandibular area. Radiological signs of bone infarction were found on some imaging, but not all. Neuropathy management was mostly directed toward the underlying cause. Overall, these observations suggest that vaso-occlusion and bone infarction could be important pathophysiological mechanisms of NCS. However, depending on the individual context, we recommend a careful evaluation to rule out differential causes, including infections, local tumors, metastatic disease, and stroke.

Numb chin syndrome in sickle cell disease: a case series of Jamaican patients

Numb chin syndrome is an uncommon presentation that has been reported as secondary to metastatic disease, trauma, and infections of the maxilla, mandible, or oral cavity. The hypoesthesia, paraesthesia, or pain are a result of injury to the inferior alveolar nerve, which is particularly vulnerable as it exits the mandible through the mandibular foramen as the mental nerve. In persons with sickle cell disease, it has been reported as a manifestation of mandibular vaso-occlusive crisis. This case series presents 13 patients with sickle cell disease who presented with numb chin syndrome, the largest number of cases that has been described in the literature to date. The report illustrates the wide variety of presentations and therefore possible differential diagnoses to consider. In this case series, the symptoms were associated with vaso-occlusive crises, allergic reactions, dental infections, malignancy, rheumatoid arthritis, and pregnancy. Most appeared to be self-limiting; however, one patient was having his second episode, and the numbness has persisted in three patients. The series illustrates that it is important not only to ensure that the source of the local vaso-occlusive crisis is treated, but also to not miss important differentials such as metastatic disease, where this can be the first presentation of malignancy and would represent a very poor prognosis. There is no reported successful treatment for the hypoesthesia in this case series, and this presents an area for further research.

Numb Chin Syndrome Leading to a Diagnosis of Salivary Ductal Adenocarcinoma: A Case Report and Review of the Literature

Numb chin syndrome (NCS) refers to a rare sensory neuropathy characterized by numbness of the chin within the distribution of the mental or inferior alveolar nerve. Although NCS is usually caused by a benign process, it should not be underestimated and a thorough diagnostic evaluation for a new or known progressive malignancy should always be performed. Here, we report a case of salivary ductal adenocarcinoma that mimicked a pulpitis and periodontitis in its early presentation accompanied by numbness of chin. The course and diagnosis of this case are discussed, and a brief review of the literature is presented. It is hoped for clinicians to keep the malignant possibility of NCS in mind and take a thorough examination.