Bilateral numb chin syndrome leading to a diagnosis of Burkitt's cell acute lymphocytic leukemia: a case report and literature review.

Numb chin syndrome (NCS), also known as mental nerve neuropathy, is characterized by facial and oral numbness restricted to the distribution of the mental nerve. Although not a common neuropathy, the clinical importance of this syndrome is its frequent association with malignancies, particularly breast cancer and lymphoma. In this paper, we present a rare case of Burkitt cell acute lymphocytic leukemia initially presenting with bilateral NCS. In this case, no abnormalities were detected on initial blood tests and radiologic investigations except for partial loss of lamina dura around mandibular teeth. Furthermore, we found no evidence of any other signs of central nervous system involvement apart from NCS. Nevertheless, the patient continued to experience severe bilateral mandibular pain and paresthesia, prompting us to repeat the blood studies. These showed lymphomatous cells, yielding the diagnosis of leukemia 37 days after the original presentation. When a patient presents with the extremely unusual symptoms of bilateral numbness of lower lip and chin, we should suspect the presence of a malignancy even in the absence of any relevant past history. If the initial radiologic investigations and blood tests reveal no abnormalities, malignancy should not be removed from the differential diagnosis until a definite cause has been found.