Cysts may arise anywhere in the larynx. Three types are common:
1, Inclusion cysts are sturdy walled, lined by squamous epithelium and contain keratin debris and cholesterol clefts.
2, Oncocytic retention cysts are thin walled, lined by thin cuboidal cells and contain mucous.
Both types probably originate from ductal elements and may contain lymphocytes and plasma cells. The source of ductal elements along the free edge of the vocal folds is open to conjecture, there being no mature glands in this location.
3, Occlusion cysts originate from the laryngeal ventricle.
Inclusion cysts and oncocytic retension cysts appear as a smoothly rounded mass immediately below the overlying epithelium. When on the free edge of the vocal fold, the oncocytic inclusion cyst often connects with the underlying vocal ligament and/or with the overlying epithelium.
Epithelium overlying both cyst types may develop a benign, protective keratosis, and that on the fold opposite the cyst frequently forms a nodule; on removal of the cyst, these resolve. Both cysts increase the mass and stiffness of the fold resulting in asymmetry of the vocal fold wave, and incomplete closure of the folds. The vocal disorder is perceived early as difficulty with vocal control, and later as hoarseness and breathiness. Cysts elsewhere produce no symptoms unless they become quite large.
These cysts occur in both sexes at any age. There is no proven etiology, although patients with cysts along the free edge of the fold often are vocally hyperactive.
Treatment of cysts, except for those arising on the free edge of the vocal fold, is simple unroofing (marsupialization). Cysts arising along the free edge of the vocal folds are treated by a variety of microsurgical techniques, each intending to remove the cyst while preserving form of the vocal fold as much as possible; however, some disturbance of form is inevitable. The vocal effects, if any, of minor disturbance of the vocal fold cover have not been documented.
The inclusion cyst is dissected out with microscissors after making a mucosal incision parallel to the fold edge on the upper surface of the ventricle then dissecting the (micro) flap medially to expose the cyst .
Video By Steven M Zeitels MD FACS
A helpful preliminary step is injection of saline plus epinephrine 1/100,000 into the subepithelial loose connective tissue about the cyst. This provides an element of hydro-dissection and markedly reduces bleeding. The mucosa first is dissected from the cyst, following which the cyst is dissected from the body of the fold. There is no excision of overlying mucosa and trauma to the subepithelial tissue is minimal because the inclusion cyst is easy to dissect. Post cyst removal, the flap is replaced without suturing.
Submucosal dissection of the thin walled oncocytic retention cyst, however, is difficult. Traction on the cyst is liable to cause rupture and should be avoided. Rarely is the cyst delivered intact so there is always risk of recurrence. The post excision wound should be carefully examined for epithelial remnants and or the presence of multiple cysts. Marsupialization of the retention cyst by simple unroofing is technically quite easy and avoids recurrence. Although there is some slight mucosal loss, the main disadvantage is that the vocal fold edge at the end of the operation is not smooth and looks funny.
None of these techniques has been proven to be superior; all typically result in improvement of the pre-operative voice. Reactive nodules on the opposing vocal fold resolve spontaneously following removal of the cyst.
Charles W Vaughan MD