Epiglottic cyst, located in the key position of upper airway, often causes lump throat. A huge epiglottic cyst may impendingly obstruct the airway. It may keep silent till it is noted accidentally in otorhinolaryngologic physical examination or general anesthesia intubation. A 29-year-old male presented lump throat for more than a month. At our hospital, fiberoptic laryngoscopy revealed a smooth protruding mass on the left side of lingual surface of his epiglottis. An epiglottic neoplasm was impressed, and micro-laryngeal surgery was scheduled. Under oral intubation general anesthesia, a mass with the size of 2.3×1.2 cm was excised. Pathologic study reported a retention cyst. According to the classification of DeSanto and Newman, it was an epithelial ductal cyst. We present the case and inform that a huge epiglottic cyst should be diagnosed and treated early, or it may lead to impending airway obstruction.