A nine-year-old girl presented with a four-day history of a growing mass under the right side of her tongue. The mass had been steadily increasing in size, but was not affecting her ability to swallow, speak, chew or breathe. The lesion was not tender or painful. It was light blue in colour. The patient had previously been well and had not experienced any recent nausea, vomiting, fever or weight loss. She had no history of oral trauma.