Pathology of the Head and Neck

200 N. Gale · A. Cardesa · N. Zidar7aFig. 7.1. Ductal cyst. a Large cyst arises from the right ventricle.b Ductal cyst is covered in ductal epithelium and filled with mucinbcan be found anywhere in the larynx [10, 177]. DCs originatefrom an obstruction of the glandular ducts, causedmainly by chronic inflammation. They are mainly locatedon the vocal cords, ventricle of Morgagni , ventricularfolds , aryepiglottic folds , and on the pharyngeal side ofthe epiglottis, where they tend to be larger, even up to7.5 cm in diameter (Fig. 7.1a) [14, 177].The origin of a so-called epidermoid cyst of the vocalcord is probably related to microtraumatic inclusion ofsmall fragments of squamous epithelium into the subepithelialtissue or to the remnants of the vocal cord sulcus[251]. These cysts are usually smaller than other laryngealretention cysts , measuring 1–4 mm and not exceeding10 mm in diameter [80].Laryngoscopically, ductal cysts are seen as a sharplydelineated spherical protrusion, the overlying mucosa issmooth and stretched. Larger cysts, mainly in newbornsor in small children, can obstruct breathing.The histological picture of DCs is influenced by origin.Laryngeal retention cysts are covered in doublelayeredcylindrical, cuboidal or flattened ductal epithelium(Fig. 7.1b) . Squamous or oncocytic metaplasia ofthe ductal epithelium, partial or complete, is frequentlypresent. Classical “epidermoid” or keratinising cystsof the vocal cords are usually lined with atrophic keratinisingepithelium with intraluminal stratified basophilickeratin scales . The therapy of choice for DC is surgicalremoval.7.2.5 Oncocytic CystAlthough the oncocytic lesions dominate in the parotidgland, they may appear in the minor salivary glands ofthe upper aerodigestive tract, including the larynx. Awhole spectrum of oncocytic laryngeal lesions has beenobserved, ranging from focal to diffuse oncocytic metaplasia,papillary cystic hyperplastic lesions to benignand malignant tumours (the latter occur mainly in thesinonasal and palatal region) [44]. On the other hand, ithas been suggested that all these lesions, variously calledoncocytic cyst (OC), oncocytic papillary cystadenoma,oncocytoma, oncocytic adenomatous hyperplasia, morelikely belong to non-neoplastic rather than to true neoplasticlesions [193, 265, 291]. This opinion has beensupported by the various extent of oncocytic metaplasiain the laryngeal minor salivary glands, as well as by theoccasional appearance of multiple cystic lesions [84, 111,230, 387].Oncocytes are enlarged cells with characteristicgranular eosinophilic cytoplasm, caused by an increasednumber of tightly packed abnormal mitochondria,and small, dense, darkly stained nuclei. The exactcause of oncocytic metaplasia remains unknown,but it is related to the process of aging and especiallyto disturbance of the organisation of the mitochondrialenzymes [238]. Laryngeal OCs may show focal,inconspicuous or extensive proliferation of oncocytes,mainly with unilocular or multilocular cystic formationswith papillary projections, resembling the Warthin’stumour [119].Laryngeal OCs probably represent a separate clinicopathologicentity, showing typical age group, locationand histopathologic features. They occur on the falsevocal cords and ventricles in middle-aged to elderly personswith hoarseness or a cough as the leading symptoms[216, 265, 283, 304]. Clinically, OCs appear as solitarypolypoid lesions in the subepithelial stroma, while