A 39-year-old white woman was referred for evaluation of swelling of the floor of the mouth and neck. The lesion had been present for 3 to 4 months with progressive enlargement. The patient denied any fever, pain, chills, or airway compromise. She did complain of biting the left floor of the mouth when chewing. The patient’s medical history was significant for hepatitis A in the past, previous appendectomy, and 3 pregnancies. She denied taking any medications and reported an allergy to silk tape. The patient did admit to smoking and denied alcohol use. Examination of the head and neck was remarkable for swelling of the left floor of the mouth that extended down into the left submandibular space and submental space. The lesion was fluctuant on palpation but nontender, and no lymphadenopathy was noted. The patient denied any difficulty with swallowing or change in quality of voice (Figs 1A, B). Panoramic radiography showed no evidence of stone formation. A computed tomography scan with contrast medium revealed a large, well-demarcated, hypodense cystic lesion in the left floor of the mouth. The mass appeared to extend inferiorly and anteriorly to a level just beneath the hyoid bone. The surrounding soft tissues appeared normal (Fig 2).