The aim of this report was to describe the computed tomography features of injected carboxymethylcellulose and how it can be mistaken for tumor recurrence. Carboxymethylcellulose is a low-density injectable indicated for short-term vocal fold augmentation. When used in patients with head and neck cancer, differentiating this agent from a neoplastic recurrence can be difficult on imaging. The imaging findings of five patients who received carboxymethylcellulose augmentation are presented to illustrate a potential pitfall of image interpretation. When injectable carboxymethylcellulose is used in cancer patients, knowledge of the injection sites, material used, and procedural history can avoid misinterpretation of monitory imaging.