[Numb chin syndrome caused by biphosphonates-induced osteonecrosis of the jaw].
BACKGROUND
Numb chin syndrome is caused by a mental or inferior alveolar nerve neuropathy. Traumatic and infectious injuries are the most frequent causes of the syndrome but, if an evident cause does not exist, a neoplastic etiology must be investigated. Other causes of the numb chin syndrome are rare.


METHODS
A 73-year-old woman had had a diagnosis of metastatic breast cancer and was been treated with zoledronic acid. She attended because of hypoesthesia and dysesthesia of the chin congruent with mental nerve distribution. A computed tomography of the jaw showed an osteolytic lesion with central bone sequestration, so biphosphonate-induced osteonecrosis of the jaw was diagnosed. After zoledronic acid was withdrawn, clinical neuropathy and imaging findings remained stable.


CONCLUSIONS
Biphosphonates-induced osteonecrosis of the jaw is a recently described condition. It has been rarely reported as a cause for numb chin syndrome. In the future, osteonecrosis of the jaw must be considered in the differential diagnosis of this syndrome in cancer patients treated with biphosphonates.
Sierra-Hidalgo
F
F
Servicio de Neurología, Hospital Universitario 12 de Octubre, Madrid, Spain. fsierra.hdoc@salud.madrid.org
de Pablo-Fernández
E
E
Correas-Callero
E
E
Villarejo-Galende
A
A
D000368:Aged; D050071:Bone Density Conservation Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy; D002680:Chin / Q000294:innervation / Q000473:pathology; D004164:Diphosphonates / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000009:adverse effects* / Q000627:therapeutic use; D007571:Jaw Diseases / Q000139:chemically induced / Q000150:complications / Q000473:pathology; D008340:Mandibular Nerve / Q000473:pathology*; D010020:Osteonecrosis / Q000139:chemically induced / Q000150:complications / Q000473:pathology; D013577:Syndrome; D000077211:Zoledronic Acid
D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007093:Imidazoles; D000077211:Zoledronic Acid