t1-weighted images and high signal intensity on t2-weighted images. the tooth itself is a zone of signal void. the lining of the cyst is thin with regular thickness and may show slight enhancement after contrast injection. treatment and prognosis the treatment of choice for dentigerous cyst is enucleation along with extraction of the impacted teeth. if eruption of the unerupted tooth is considered feasible, the tooth may be left in place after partial removal of the cyst wall. orthodontic treatment may subsequently be required to assist eruption. similarly, if displacement of the associated tooth by the cyst has occurred and extraction may prove to be difficult, orthodontic movement of the tooth to a more advantageous location for extraction may be accomplished. marsupialization may also be used to treat large dentigerous cysts. this permits the decompression of the cyst, with a resulting decrease in the size of the bone defect. the cyst can then be excised at a later date, with a less extensive surgical procedure. the prognosis for the dentigerous cyst is excellent, and recurrence is rare. this is related to the exhausted nature of the reduced enamel epithelium, which has differentiated and formed tooth crown enamel before developing into a cyst. nevertheless, several potential complications must be considered. the possibility that the lining of a dentigerous cyst might undergo neoplastic transformation to an ameloblastoma has been well-documented. mourshed showed that 33% of ameloblastomas arose from the epithelial lining of a dentigerous cyst. although undeniably this can occur, the frequency of such neoplastic transformation is low. in addition, a squamous cell carcinoma may rarely arise in the lining of a dentigerous cyst. transformation from normal epithelial cyst lining to scc is due to chronic inflammation. it is likely that some intraosseous mucoepidermoid carcinomas develop from mucous cells in the lining of a dentigerous cyst. malignancy in the cyst wall is usually unexpected at the time of presentation and the diagnosis is usually made following enucleation. jagged or irregular margins with indentations and indistinct borders are considered to be suggestive of possible malignant change. due to the potential for occurrence of an odontogenic keratocyst or the development of an ameloblastoma or, more rarely, mucoepidermoid carcinoma, all such lesions, when excised, should be submitted for histopathologic evaluation. differential diagnosis the differential diagnoses of dentigerous cysts are as follows: radicular cyst an odontogenic cyst that is a sequela of periapical granuloma in a carious tooth. odontogenic keratocyst (okc) this is often multilocular and most commonly located in the body or the ramus of the mandible. histologically, the epithelium is uniform in nature, usually four to eight cells in thickness. the basilar layer consists of a palisaded row of cuboidal to columnar cells that may demonstrate hyperchromatism. characteristically, a corrugated or wavy layer of parakeratin is produced on the epithelial surface and desquamated keratin may be present in the cyst lumen. odontogenic keratocysts do not result in the same degree of bony expansion as dentigerous cysts and teeth resorption are less likely to be seen in association with odontogenic keratocysts. in addition, dentigerous cysts are more likely to have smooth periphery and odontogenic keratocysts are more likely to display a scalloped periphery. unicystic ameloblastoma the most common radiolucent, benign odontogenic tumor, which may be unilocular or multilocular. it may result in expansion and destruction of the maxilla and mandible. it is not possible to differentiate unicystic ameloblastomas from dentigerous cysts with clinical and radiographic examinations. histopathologic examination revealed that the basilar cells in unicystic ameloblastoma become columnar and demonstrate prominent nuclear hyperchromatism. the polarization of nuclei may be away from the basement membrane (reverse polarization). besides, the superficial epithelial layers may become loosely arranged and resemble the stellate reticulum of the enamel organ. pindborg tumor a rare odontogenic tumor that is radiolucent with well-defined border and associated calcified radiopaque foci. adenomatoid odontogenic tumor also shows similar features as dentigerous cyst; however, the differentiation is by the presence of intra-cystic radio-opaque structures. in younger patients, the periapical radiolucencies associated with deciduous teeth may mimic pericoronal radiolucencies of succedaneous permanent teeth and may result in a false impression of dentigerous cyst. a definitive diagnosis will not be made based on radiographs alone. the diagnosis can only be confirmed by histopathological examination. odontoma a lytic lesion that is frequently accompanied by amorphous calcification. odontogenic fibromyxoma usually has multiple radiolucent areas of varying size and bony septations, but unilocular lesions have also been described. cementoma a lytic lesion that is most often seen with amorphous calcification.