Diagnosing the cause of paraesthesia can be challenging. A patient with an unremarkable medical history, non-smoker and no known allergies, presented with paraesthesia in the distribution of the mental nerve with no obvious dento-alveolar pathology. After further investigations the patient was found to have multiple brain metastases and a solitary mandibular deposit, with the primary site being an adenocarcinoma of the lung. CPD/Clinical Relevance: As dental professionals, knowledge of head and neck manifestations of systemic conditions is required if prompt diagnosis and treatment is to occur, which will subsequently improve patient health outcomes.