Pathology of the Head and Neck

Maxillofacial Skeleton and Teeth Chapter 4 107of an erupting tooth. Mostly, these cysts are short-lived,rupturing with the progressive eruption of the associatedtooth. They are lined by squamous epithelium that isthickened due to inflammatory changes in the underlyingconnective tissue and thus similar to the lining of aradicular cyst.4.3.2.2 Lateral Periodontal CystLateral periodontal cysts are rare lesions, derived fromodontogenic epithelial remnants, and occurring on thelateral aspect or between the roots of vital teeth (Fig. 4.3)[166]. They are lined by a thin, non-keratinising squamousor cuboidal epithelium with focal, plaque-likethickenings consisting of clear cells that may containglycogen (Fig. 4.7) [150].Lateral periodontal cysts do not cause any symptoms.They are fortuitous findings on radiographs where theypresent as a well-demarcated radiolucency on the lateralsurface of a tooth root. Simple enucleation is adequatetreatment.The botryoid odontogenic cyst represents a multilocularform of the lateral periodontal cyst [54]. Treatmentby curettage is the most appropriate treatment, but recurrencesmay occur [52].Fig. 4.7. Lateral periodontal cyst. The epithelial lining formsplaques consisting of clear cells4.3.2.3 Glandular Odontogenic CystThe glandular odontogenic cyst , also called sialo-odontogeniccyst is a rare cystic lesion characterised by an epitheliallining with cuboidal or columnar cells both at thesurface and lining crypts or cyst-like spaces within thethickness of the epithelium [34, 73].The lining epithelium is partly non-keratinising,squamous and with focal thickenings similar to theplaques in the lateral periodontal cyst and the botryoidodontogenic cyst. There may be a surface layer ofeosinophilic cuboidal or columnar cells that can havecilia and may form papillary projections. Some superficialcells assume an apocrine appearance. Also, mucus-producingcells may be present. Focally, the epitheliumshows areas of increased thickness in which glandularspaces are formed. Moreover, the epithelial cellsmay lie in spherical structures with a whorled appearance(Fig. 4.8).Mucous cells and cuboidal cells with cilia may alsooccur in other jaw cysts, but the latter lack the other epithelialfeatures described above. Mucous cells and nonkeratinisingsquamous epithelium also occur in mucoepidermoidcarcinoma [91, 177]. However, epithelialplaques consisting of clear cells are not a feature of thislatter lesion.The glandular odontogenic cyst most commonly affectsthe body of the mandible and the most prominentFig. 4.8. Epithelial lining of glandular odontogenic cyst showingintraepithelial duct formation and apocrine differentiation at thesurfacesymptom is painless swelling [126]. Treatment may beconservative, but recurrence may occur [48].4.3.2.4 Odontogenic KeratocystOdontogenic keratocyst , formerly also called primordialcyst , is defined by the presence of an epithelial lining notexceeding 10 cell layers in thickness, palisading of thebasal cells, and a parakeratinised, corrugated surface[114].Odontogenic keratocysts are common lesions [147,148, 149]. They show a wide age range with a peak frequencyin the 2nd and 3rd decades, are more commonin males then in females and occur twice as frequently inthe mandible as in the maxilla. Involvement of the gingivalsoft tissues has also been reported [26]. They alsooccur in cases of nevoid basal cell carcinoma syndromeand in patients with Marfan’s syndrome [11, 50, 186].