Silent Epiglottic Cyst Emerges as Anesthesia Hazard After Induction

Preoperative airway assessment traditionally focuses on observable signs—neck mobility, mouth opening, jaw size, snoring, hoarseness, and dysphagia. A 60‑year‑old woman presented for laparoscopic cholecystectomy after being cleared on this evaluation. She reported no throat‑related symptoms.

During induction, mask ventilation became problematic, and video laryngoscopy revealed the cause: a large cyst covering the epiglottis and obscuring the glottic opening. The initial intubation attempt failed.

The anesthesiologists from Affiliated Yangming Hospital of Ningbo University in Zhejiang, China, documented the case in a preprint on Research Square. They highlight a concealed risk: a benign lesion that often yields no patient‑reported symptoms yet can become life‑threatening when anesthesia eliminates protective muscle tone.

A Benign Lump in the Worst Possible Location

Epiglottic cysts are the most frequent laryngeal cysts, arising when a mucous gland duct becomes obstructed and secretions accumulate. These cysts are benign and can appear at any age. Historical series report an incidence of roughly 0.08 % in routine laryngoscopies, with larger cysts occurring in about 0.02 % of cases.

The clinical picture varies. Congenital laryngeal cysts typically present early with clear airway obstruction, as seen in a newborn case where the glottis was completely blocked. In contrast, acquired cysts in adults are often asymptomatic. Patients may later notice a foreign‑body sensation, mild throat discomfort, or occasional swallowing difficulty, but significant breathing problems usually develop only when the lesion enlarges.

Consequently, such lesions can grow unnoticed, leaving patients without any antecedent complaints to mention during the preoperative visit.

Awake, the Epiglottis Stays Out of the Way

While conscious, normal muscle tone keeps the tongue and epiglottis positioned away from the laryngeal inlet. Anesthetic agents and neuromuscular blockers reduce this tone, allowing soft tissues—and any cyst on the epiglottis—to shift posteriorly and potentially obstruct the airway.

Attempting to displace the cyst with a laryngoscope blade carries its own danger. Rupture can release cyst fluid into the trachea, precipitating airway spasm, glottic closure, hypoxia, bradycardia, and even cardiac arrest, as detailed in the Journal of Anaesthesiology Clinical Pharmacology.

When It Goes Wrong, It Goes Wrong in About Fifteen Minutes

A peer‑reviewed case in BMC Anesthesiology illustrates the potential cascade. A 61‑year‑old man scheduled for arthroscopic heel spur removal had a reassuring airway assessment (ASA II, Mallampati I) and no prior intubation difficulties. After induction with sufentanil, cisatracurium, and propofol, mask ventilation became impossible, and a size 4 laryngeal mask failed despite adjustments. Video laryngoscopy uncovered a 2 × 3 cm cyst covering the entire epiglottic surface and completely hiding the vocal cords. An ear, nose, and throat surgeon was called, and the team used the endotracheal tube tip to lift the cyst, partially expose the glottis, and pass a 6.5‑mm tube. The entire sequence took about 15 minutes, with oxygen saturation dipping to 85 % for less than a minute.

In some instances, the cyst cannot be dislodged. A Cureus report described an adult with a totally obstructing epiglottic cyst where side‑to‑side laryngeal manipulation and blade techniques carried a high rupture risk. The team proceeded to a tracheostomy under local anesthesia. Even when a cyst is known pre‑operatively, it can still cause difficulty, as a 2023 Medicine report noted—a patient slated for cyst removal still experienced airway compromise after induction, eventually resolved with video laryngoscopy.

What This Does Not Mean for People Facing Surgery

The Chinese preprint represents a single, unreviewed case and cannot define the true incidence of asymptomatic epiglottic cysts causing anesthetic complications. Such data remain scarce because these lesions are usually incidental findings.

Routine throat scanning before every elective procedure is not advocated. The consensus from the published literature is more modest: a thorough preoperative airway assessment is essential, video laryngoscopy should be employed promptly after any ventilation difficulty, and early assistance should be summoned. New technology does not replace the need for mastery of front‑of‑neck rescue techniques, and calling for help remains critical in every scenario.

For patients, the key advice is straightforward. Report any throat‑related symptoms—no matter how minor—such as a persistent sensation of something in the throat, voice changes, snoring, or swallowing difficulty. Disclose any history of prior difficult intubation, even if it was not formally documented. These details guide the anesthesia team’s planning and management.

Key Questions Answered

What is an epiglottic cyst?

A benign, fluid‑filled growth on the epiglottis that develops when a mucous gland duct becomes blocked and secretions accumulate. It is the most common type of laryngeal cyst and can occur at any age.

Why was it dangerous during surgery?

Anesthetic drugs and muscle relaxants remove the natural muscle tone that keeps the epiglottis away from the airway. A cyst that is asymptomatic while awake can then fall across the glottic opening, obscuring the view needed for intubation.

What happened in the Chinese case?

After induction, mask ventilation failed and the first intubation attempt was unsuccessful. Video laryngoscopy identified the cyst covering the glottis, allowing the team to secure the airway. The report remains a preprint and has not undergone peer review.

Can preoperative assessment detect these cysts?

Standard airway checks rely on symptoms and physical measurements and are not reliable for detecting asymptomatic epiglottic cysts. In the cited case, the patient had the most reassuring ASA and Mallampati grades yet still experienced a difficult airway.

Why not just push the cyst out of the way?

Manipulating the cyst with a laryngoscope blade risks rupture, which can cause cyst fluid to spill into the trachea. This spillage has been linked to airway spasm, glottic closure, hypoxia, bradycardia, and cardiac arrest.

What should patients tell their anesthesia team?

Any persistent throat sensation, voice change, snoring, or swallowing difficulty—even if it seems trivial—and any history of previous difficult intubation should be disclosed. This information enables the anesthesia team to plan appropriately and ensure patient safety.

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