Numb chin syndrome: a nonmetastatic neurological manifestation of malignancy.

Numb chin syndrome, sometimes called numb lip syndrome, is an uncommon but well-recognized symptom in medical oncology. It may be a nonmetastatic neurological manifestation of malignancy, often with no clinically visible pathology. We report a case of a 79-year-old woman with widespread metastatic disease secondary to breast carcinoma who presented with a left-sided numb lip and chin.