Endoscopic Transoral Coblation Resection of an Aryepiglottic Fold Schwannoma Presenting With a 10-Year Cough: A Case Report

Surgical Procedure

Under general anesthesia, a laryngoscope was inserted to expose the glottis. Endoscopic examination revealed a round, well-circumscribed tumor located in the supraglottic region, specifically at the posterior margin of the right aryepiglottic fold. The tumor was gently grasped with a cup forceps and retracted medially. Coblation was then used to dissect precisely along the tumor margins, achieving complete en bloc resection. Hemostasis was obtained with an epinephrine-soaked cotton pad. The total estimated intraoperative blood loss was approximately 1 mL.

Postoperative Results

The resected specimen measured approximately 1.2×1.0 cm (Figure 2A). Histopathological and immunohistochemical analyses confirmed a benign spindle cell mesenchymal tumor consistent with schwannoma (S-100 and SOX10 positive, focal CD34 expression, Ki-67 1%). To prevent postoperative bleeding and laryngeal edema, the patient received nasogastric tube feeding for 7 days. Postoperatively, her chronic cough improved markedly, facial nerve function was House-Brackmann grade I, and swallowing function was normal. At 6-month follow-up, laryngoscopy showed well-healed mucosa with no tumor recurrence(Figure 2B and C).OPEN IN VIEWER

1. “Deceptive” Laryngeal Disorders: Why do Middle-Aged Women Present Mainly With a Single Long-Term Cough?

The patient’s long-standing (10-year) cough as the sole symptom is noteworthy, as hoarseness or dysphagia—typical “alarm” signs of laryngeal neoplasms—were absent. ⁶ This unusual presentation may be related to the complex anatomy of the supraglottic larynx.Sensory innervation of the supraglottic larynx is provided almost exclusively by the internal branch of the superior laryngeal nerve (IbSLN). ⁷ The IbSLN gives off three divisions, with its middle branch running along the aryepiglottic fold—the exact tumor location in our patient—which is richly supplied with mechanoreceptors and chemoreceptors. ⁸ Activation of these receptors initiates the cough reflex arc via the IbSLN and vagus nerve to the nucleus tractus solitarius. Mechanical stimulation of the supraglottic area produces cough exclusively dependent on an intact superior laryngeal nerve. ⁹ Thus, a small tumor in the aryepiglottic fold can mechanically trigger cough without affecting the vocal folds or recurrent laryngeal nerve, explaining the absence of hoarseness. Furthermore, schwannomas grow exceptionally slowly-consistent with the patient’s decade-long unchanged dry cough—indicating chronic, low-grade mechanical stimulation of IbSLN terminals without motor nerve invasion.

From a clinical teaching perspective, this case reinforces two critical lessons. First, an isolated chronic cough, even without classic laryngeal symptoms, should not be automatically attributed to benign causes such as postnasal drip, asthma, or reflux. Up to 61% of patients with chronic cough and a normal chest radiograph harbor an underlying laryngeal lesion, and although most are benign, malignancy must be ruled out. ¹⁰ Second, laryngoscopy should be performed early in any patient with unexplained chronic cough, and submucosal lesions must be considered even when the overlying mucosa appears normal—so-called silent supraglottic neoplasms are known to delay diagnosis.

2. Transoral Coblation for Aryepiglottic Schwannomas: A Comparative Review of Surgical Techniques

For schwannomas located in the aryepiglottic fold, a variety of surgical approaches are available. These can be broadly categorized into: (1)open transcervical approaches (e.g., laryngofissure), (2)transoral laser microsurgery(TLM), (3)transoral endoscopic non-laser techniques, including cold-steel microsurgery, radiofrequency coblation, and transoral robotic surgery (TORS). Compared with traditional open surgery, the advantages of transoral coblation are clear. A laryngofissure approach typically requires a tracheostomy for airway protection and carries the risk of postoperative vocal fatigue and dysphonia. Although it may be necessary for voluminous or deeply invasive tumors, the procedure inevitably injures overlying laryngeal mucosa and compromises normal laryngeal architecture. ¹¹ In contrast, coblation performed through the natural orifice leaves no external scar, avoids tracheostomy, and enables rapid recovery of voice and swallowing. ¹²

A more nuanced comparison is between coblation and CO₂ laser—the current reference standard for transoral laryngeal surgery. While CO₂ laser is effective, it has limitations in hemostasis and produces a zone of thermal damage up to 500 μm wide. ¹³ Coblation, using a bipolar radiofrequency field at 40–70 °C, induces minimal collateral thermal spread (<100 μm) while providing simultaneous cutting and coagulation. ¹⁴ This difference is clinically relevant in the aryepiglottic fold, where preservation of sensory innervation (via the internal branch of the superior laryngeal nerve) and motor function is paramount. Recent literature has begun to advocate coblation for laryngeal schwannomas. Wang et al concluded that transoral endoscopic excision, particularly when performed with coblation, is highly recommended for its excellent visualization and ability to completely excise the tumor. ¹⁵ In a canine vocal fold model, coblation resulted in complete re-epithelialization by postoperative day 7 with no injury to the underlying vocalis muscle, and less inflammation than that reported for CO₂ laser. ¹⁶ Moreover, in a histopathological comparative study, coblation achieved thermal damage depths comparable to CO₂ laser, and for a benign encapsulated schwannoma, minor irregularities at the cut edge do not affect complete resection or recurrence. ¹⁷ Compared with TORS, coblation offers similar advantages of a transoral route but with significantly lower cost, shorter learning curve, and broader availability, making it a more cost-effective option for benign lesions. ¹⁸ The present case aligns with these findings: coblation provided a blood-less surgical field, allowed meticulous separation of the tumor from the aryepiglottic fold, and permitted immediate extubation.

3. Limitations and Outlook

This report has several limitations. First, the patient declined preoperative MRI or CT, which could have better defined the tumor’s extent and its relationship with the paraglottic space. However, intraoperative findings confirmed a well-encapsulated lesion that was completely excisable. Second, longer follow-up is ongoing, although the benign biological behavior of this tumor suggests a low risk of late recurrence. Third, regarding the technique itself, coblation may be less suitable for highly vascular or paraglottic-extending tumors. Despite these limitations, transoral low-temperature coblation remains a safe, effective, and highly minimally invasive option for aryepiglottic schwannomas. It offers oncologic safety comparable to CO₂ laser, with potentially superior hemostasis and a favorable tissue-sparing profile. We recommend that coblation be considered alongside CO₂ laser as a first-line transoral technique for these rare benign tumors.