Читать книгу Shear's Cysts of the Oral and Maxillofacial Regions - Paul M. Speight - Страница 76

Paradental cysts associated with third molars are removed by enucleation of the cyst along with extraction of the associated tooth. Occasionally, the whole specimen is received intact (Figure 4.6) and will show that the cyst is a sac‐like mass attached at the cementoenamel junction and located on the buccal aspect of the tooth roots. This is in contrast to a dentigerous cyst, which is also attached to the cementoenamel junction, but surrounds the crown of the tooth (see Figures 5.18 and 5.19). Careful examination with a probe will show that the lumen of the cyst is continuous with the periodontal or pericoronal pocket (Figure 4.6b). This appearance is virtually diagnostic of an inflammatory collateral cyst.

Mandibular buccal bifurcation cysts are usually removed by enucleation or curettage and the tooth is left in situ. In this case the pathologist will often receive fragments of soft tissue that in places may resemble a cyst wall.

Histological examination shows non‐specific features that are indistinguishable from radicular cyst and it will be impossible to make a diagnosis without consideration of the clinical findings and review of the radiology. The cysts are lined by a hyperplastic, non‐keratinised, stratified squamous epithelium, which may be spongiotic and of varying thickness. There is an intense chronic or mixed inflammatory cell infiltrate associated with the hyperplastic epithelium and in the adjacent fibrous capsule (Figure 4.7). As in radicular cysts, haemosiderin deposits, hyaline bodies, or accumulations of cholesterol crystals may be seen. An opening into the cyst lumen may also be seen and the epithelial lining may be continuous with sulcular or gingival epithelium at the periphery. Occasional cases may show focal accumulations of foreign body–type giant cells, consistent with impaction of food particles (Fowler and Brannon 1989 ; Colgan et al. 2002 ).