Numb chin syndrome (NCS) is defined as reduced or absent sensation in the chin and lower lip within the distribution of the mental or inferior alveolar nerves. Although commonly associated with local trauma, NCS can indicate an underlying malignancy or can be the presenting symptom of cancer recurrence. We describe the first pediatric patient with acute myeloid leukemia (AML) who presents with NCS as a sign of AML recurrence post allogeneic hematopoietic cell transplantation. We also review the current literature on acute leukemia and NCS.