Neuropsychiatric Symptoms in a p16-Positive Tongue Carcinoma Patient: An Unexpected Diagnosis.

Differential diagnosis of neuropsychiatric symptoms in a patient with an underlying malignancy is exhaustive. 5-fluorouracil (5-FU) is one of the most widely used chemotherapy agents and it is often used as the first-line regimen in head and neck malignancies. We present a case of an elderly female with an underlying locally advanced p16-positive squamous cell carcinoma of the tongue who presented with manic symptoms for one week after cycle 2 of chemotherapy.