Laryngocele presented as Neck Mass
Laryngocele is a congenital anomalous air sac communicating with the cavity of the larynx, which may bulge outward on the neck. It may also be acquired, seen in glassblowers and trumpet blowers due to continual forced expiration producing increased pressures in the larynx which leads to dilatation of the laryngeal ventricle. It is also seen in people with chronic obstructive airway disease.
History: This benign tumor was first described by Virchow in 1863. He defined it as an anomalous air sac communicating with the laryngeal ventricle. He initially used the term “laryngocele ventricularis” to describe this condition.
Types: A laryngocele is an air filled mass of the larynx, connecting to the lumen of the larynx through the ventricle. The ventricle is the space above the vocal cords and below the false vocal cords. The anterior part of the ventricle, called the saccule, can become enlarged and filled with air and/or mucus.
Laryngocele can be confined within the voice box (internal laryngocele) or may extend beyond the larynx into the neck (external laryngocele) through the thyrohyoid membrane.
If the communication between the laryngocele and the laryngeal lumen gets occluded, fluid may get accumulated within the sac. If the accumulated fluid is mucoid in nature the term laryngomucocele is used. If it is filled with pus then laryngopyocele is used to describe the mass.
Pathophysiology: Factors that cause an increase in intra laryngeal pressure like coughing, straining, blowing wind instruments may cause laryngocele. Gradual weakening of the laryngeal tissues due to aging also plays a role in the pathophysiology of development of laryngocele. Infact laryngocele have been considered to be a health hazard in glass blowers. The neck of the saccule has been postulated to act as a one way valve allowing accumulation of air and preventing its egress.
Clinical features: Mostly laryngocele are incidentally discovered during routine laryngeal examination. Symptoms if present may include:
1. Hoarseness of voice
3. Foreign body sensation in the throat
4. Present with a neck mass close to the thyrohyoid membrane.
5. Large internal laryngocele may cause airway obstruction.
Since laryngocele may be associated with laryngeal malignancies, its presence in an old patient should prompt the examiner to diligently search for laryngeal malignancy.
Indirect laryngoscopy is diagnostic. Indirect / combined laryngocele appear as submucosal mass in the region of false vocal cord. If fibre optic laryngoscope is used these masses can be seen to enlarge during a valsalva maneuver. In pure external laryngocele endolaryngeal examination will be normal.
If combined laryngocele is presenting as a neck mass, compression will cause a hissing sound as the air escapes from it (Bryce sign) into the larynx.
Radiological examination: Plain x-ray soft tissue neck show air filled sac protruding from the soft tissues of neck. When x-ray is repeated on Valsalva maneuver the size of the mass shows increase in size. Small internal laryngocele are difficult to identify radiologically in plain films. CT scans are diagnostic.
External lateral neck approach is commonly favored by most surgeons to excise laryngocele because of its excellent exposure, minimal morbitidity and reduced chances of recurrence. To manage internal laryngocele a small portion of thyroid cartilage may have to be removed to allow adequate exposure. External and combined laryngocele can be dissected via the thyrohyoid membrane and cartilage sacrifice is not required.
The surgeon approaches the mass through a horizontal incision over natural skin crease just over the region of thyrohyoid membrane. The mass overlies this area hence there may not be any difficulty in identifying the thryohyoid membrane area. Skin flaps are elevated in the subplatysmal plane. The bulging strap muscles may be transected for better exposure of the mass. The carotid sheath is pushed posteriorly. The ansa cervicalis nerve may be adherent to the laryngocele and may be dissected out / transected if necessary. When the laryngocele is delivered there is dehiscence in the thryohyoid membrane which is closed with sutures.
Endoscopic approach: can be resorted to in small internal laryngocele. The cyst is decompressed internally. Recurrence is common in this procedure.