Numb Chin Syndrome

Abstract

"Numb chin syndrome" (NCS) refers to new-onset numbness of the lower lip and chin within the distribution of the mental or inferior alveolar nerves. While this focal numbness may be downplayed or even overlooked by patients and clinicians, in the right clinical scenario this may be the presenting symptom of an underlying malignancy. In the absence of any obvious, temporally related dental cause, there are certain conditions that clinicians should consider including orofacial and systemic malignancies as well as several inflammatory disorders. Thorough diagnostic evaluation should always be performed when no clear cause is evident. This paper will discuss the differential, recommended evaluations, and the prognosis, for a patient presenting with NCS.

Extranodal intraosseous Rosai–Dorfman disease in the lower jaw: a case report and review of the literature

“…The so called dumb chin syndrome was the first and the only manifestation of the intraosseous mandibular RDD as in most of the reported lower jaw involvements. This suggests that RDD is another lymphoproliferative neoplasia which should be included in the differential diagnosis of the dumb chin syndrome [17]. Treatment strategies which are advocated in the literature tend to depend on the form of the disease.…”

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

“…It has not been reported in China yet. NCS is caused by the lesion of the mental nerve which is one of the terminal branches of the mandibular division of the trigeminal nerve (6). Although NCS is unilateral in most cases, it may be bilateral in a few cases (10%) which may occur simultaneously or subsequently as seen in our case (7).…”

“…However, this innocuous symptom familiar to anyone having had local dental anesthesia may betray a more alarming and underlining disease. Although rare, it may be the first symptom of an underlying malignancy (6). In this case, the numbness preceded by the feeling of toothache was considered to be caused by dental problem at first.…”

“…The most common primary cancers are breast cancer, lung cancer, lymphoma, and cancers in thyroid, prostate, and colon, although melanoma, myeloma, sarcoma, and cancers in ovary, testis, salivary glands, lip, and gut have also been reported. Breast cancer and lymphoma account for most cases of NCS in adults, while acute lymphoblastic leukemia is a significant cause in children (6, 7). Histologically, adenocarcinoma originating from different tissues is the most frequent subtype reported in the literature (70%) (15).…”

“…However, a classical brain MRI protocol may sometimes not extend inferiorly enough to view the mental foramen and may therefore miss a focal mass or osseous lesion (23). In addition, the diagnostic process may require thoracic or abdominal radiographs, sonography, and, if needed, abdominal CT scans and MRI, PET-CT scans to look for primary neoplasm and its metastatic sites (6, 24). The patient in this case was once suspected as trigeminal neuralgia because the MRI showed a vessel riding across the trigeminal nerve.…”