Numb chin syndrome in cancer patients: etiology, response to treatment, and prognostic significance.

We retrospectively evaluated 42 consecutive cancer patients with numb chin syndrome (NCS). Breast cancer comprised 64% of the primary tumors, and lymphoproliferative neoplasms comprised 14%. A standard workup (including imaging of the brain, base of skull, and mandible, and CSF analysis) led to the diagnosis of a metastatic etiology in 89% of the patients. Fifty percent of the patients had mandibular metastases, 14% base-of-skull bone lesions, and 22% leptomeningeal seeding. NCS was a late manifestation of malignancy, associated with disease progression in 67% of the patients or heralding a relapse, which was often confined to the leptomeninges, in 31%. Although various therapeutic strategies led to resolution of NCS, median survival after its diagnosis was 5 months when due to bone metastases and 12 months if associated with leptomeningeal seeding.