Three patients with skin cancer had numbness isolated to one cheek, in the distribution of the infraorbital nerve. Hypesthesia also involved the medial and lateral upper incisors and canine teeth, and adjacent gingiva, sparing the more posterior teeth and gums. The molar and premolar teeth and gums are innervated by the posterior and middle superior alveolar nerves; because these structures were spared, the pathologic process was localized to the infraorbital foramen, and we could exclude involvement of the maxillary division more proximally. In two patients, cheek numbness heralded recurrent squamous cell carcinoma. Analogous anatomy at the mental foramen should help distinguish intracranial leptomeningeal from local mandibular lesions producing isolated numbness of the chin.