Cytokeratin expression patterns for distinction of odontogenic keratocysts from dentigerous and radicular cysts

BACKGROUND

The clinical outcome of treatment of odontogenic cysts differs depending on separate entities. Particular clinical relevance must be attached to the distinction between odontogenic keratocysts, which have an evident tendency to recur, and other odontogenic cysts. The aim of this study was to evaluate cytokeratin (CK) expression patterns as an additional tool for characterization of different cysts as the histomorphologic appearance often is not decisive.

METHODS

Thirty cases of dentigerous and radicular cysts respectively as well as 15 cases of odontogenic keratocysts were considered. Expression of CK 5/6, 7, 10, 13, 17, 19 and 20 was determined in addition to Ki-67 immunohistochemically.

RESULTS

Expression of CK 17 was discernible in 93.3% of the odontogenic keratocysts, but only in 35.0% of dentigerous and radicular cysts under study (P < 0.001). CK 19 could be detected in 48.3% of dentigerous and radicular cysts, whereas odontogenic keratocysts were completely negative (P < 0.002).

CONCLUSION

Immunohistochemical detection of CK 17 and 19 seems to be a valuable additional parameter distinguishing between odontogenic keratocysts and other odontogenic--especially dentigerous--cysts which clinically are likely the most significant differential diagnoses in this context. J Oral Pathol Med (2005) 34: 558-64.

Cell proliferation, apoptosis and apoptosis-related factors in odontogenic keratocysts and in dentigerous cysts

BACKGROUND

The purpose of this study was to elucidate why odontogenic keratocysts (OKC) can form cystic lesions but not tumor masses, notwithstanding their prominent proliferative activity.

METHODS

We investigated cellular proliferation, cell death, and expression of apoptosis-related proteins in the lining cells of OKCs and of dentigerous cysts (DGCs).

RESULTS

TdT-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells were observed in the surface layers of OKCs and of DGCs. However, no TUNEL-positive cells were seen in the basal or intermediate layers of both cysts. Ki67-positive ratio in the intermediate layer was the highest in OKCs. The p53-positive ratio of the intermediate layer was highest in OKCs. Bcl-2-positive cells were discernible exclusively in the basal layer of OKCs.

CONCLUSIONS

These results suggest that cellular proliferation and death is regulated in association with apoptosis-related proteins in the lining epithelia of OKCs, and subsequently those cysts are seen as cystic lesions but not as tumor masses.

The differential expression pattern of BMP-4 between the dentigerous cyst and the odontogenic keratocyst

BACKGROUND

Bone morphogenic protein-4 (BMP-4) is widely expressed in oral cavity and involved in tooth morphogenesis, cellular differentiation and proliferation. The purpose of this study was to compare the difference in expression pattern of BMP-4 in odontogenic keratocysts (OKC) and dentigerous cysts (DC).

METHODS

We evaluated 77 cysts, OKC (n = 34) or DC (n = 43). The average age of patients with OKC was 29.5 +/- 14.4 and that of patients with DC was 36.1 +/- 19.4. The male to female ratio was 20:14 for OKC and 27:16 for DC. Ten cases of OKC were recurrences. Expression of BMP-4 was determined by immunohistochemistry and in situ hybridization.

RESULTS

The intensity scales were (-) for invisible or trace staining, (+) for visible staining, and (++) for dense, strong staining. OKCs exhibited the following staining patterns: the epithelium in 15/34 specimens and the mesenchymal cells in 17/34 specimens showed (++) stain. In contrast, the staining pattern of DC was (-) for epithelium in 37/43 specimens. The mesenchymal cells showed (-) degree staining in 30/43 specimens. The difference between the groups studied was significant (P < 0.001 in epithelium and mesenchymal cells). When recurrent and non-recurrent OKC were compared BMP-4 was expressed more intensely in the recurrent cases (P = 0.036 in epithelium). The difference in BMP-4 expression in mesenchymal cells was not significant. In situ hybridization demonstrated positive mRNA probes to BMP-4 were localized in epithelium and mesenchymal cells of OKCs and DCs.

CONCLUSIONS

BMP-4 was expressed more intensely in OKC when compared with DC, and was more intensely expressed in recurrent cases.

[Odontogenic keratocyst in dentigerous position. A clinical case]

Cysts that may develop in the maxillo-mandibular region and adjacent tissues may be of odontogenic origin, non-odontogenic origin, pseudocysts, cysts associated with the maxillary sinus and those developed from the soft tissues. These may vary as to their histogenesis, frequency, behavior and treatment. This article presents the clinical case of an 18-year-old female patient with an initial radiographic diagnosis of dentigerous cyst, which after exploratory punction and surgical removal under general anesthesia yielded a final diagnosis of odontogenic keratocyst. The patient's evolution was satisfactory with a 2-year radiographic control, without evidence of recurrence.

Apoptosis-related factors in the epithelial components of dental follicles and dentigerous cysts associated with impacted third molars of the mandible

OBJECTIVE

Radiolucencies adjacent to the crowns of impacted third molars can represent follicular remnants or cysts. To clarify the possible role of apoptosis-related factors in pericoronal odontogenic tissues, expression of Fas, bcl-2, and single-stranded DNA (ssDNA) was examined in epithelial components of dental follicles (DFs) and dentigerous cysts (DCs) associated with impacted third molars of the mandible. The results were compared with immunoreactivity for Ki-67, a marker of cell proliferation.

STUDY DESIGN

Specimens of 80 DFs and 27 DCs were examined immunohistochemically using antibodies against Fas, bcl-2, ssDNA, and Ki-67.

RESULTS

Expression of Fas and ssDNA was detected in superficial epithelial cells of DFs and DCs. Expression of bcl-2 and Ki-67 was found in epithelial cells neighboring the basement membrane. The positive ratio of bcl-2 in DFs was significantly lower than that in DCs. ssDNA-positive cells were slightly more numerous in DFs, while Ki-67-positive cells were slightly more numerous in DCs. In DFs, epithelial tissues with proliferative rete processes showed significantly higher Ki-67 labeling than did those without proliferative rete processes. DFs with marked inflammatory changes showed slightly higher rates of ssDNA and Ki-67 positivity than did DFs without marked inflammation.

CONCLUSIONS

Apoptosis-related factors and proliferative marker differ between DFs and DCs. Apoptosis and cell proliferation may play a role in the pathogenesis of DCs. In DFs, expression of apoptosis-related factors and proliferative marker is most likely modulated by the morphologic characteristics of epithelial components as well as by inflammatory changes.

[Occurrence of epithelium in the soft tissues associated with routine surgical removal of 150 mandibular third molars]

BACKGROUND

The aim of the study was to classify epithelial structures (ES) and to determine the prevalence of cysts associated with mandibular third molars (M(3)).

MATERIAL AND METHOD

Sections of HE-stained soft tissue specimens and panoramic radiographs of 150 consecutive patients undergoing surgical removal of M(3) were evaluated. ES were classified as islands and/or strands of odontogenic epithelium (OE), reduced enamel epithelium (REE), stratified cyst epithelium (SCE), oral mucosa (OM), and pocket epithelium (PE). The diagnostic criteria were defined as a pericoronal translucency >2.5 mm and SCE for dentigerous cysts (DC) and a distal translucency >2.5 mm, SCE, and inflammation for inflammatory paradental cysts (IPC).

RESULTS

Median age was 24.4 years: 23.0 years for 86 (57.3%) female patients and 25.7 years for 64 (42.7%) male patients (p=0.017). ES were found in 95.3%, classified as OE in 53.3%, REE in 34.7%, SCE in 28%, OM in 30.7%, and PE in 10.7%. Both REE and SCE were found in 6%. The total number of cases with REE and/or SCE was 56.7%. Median age of cases with SCE was 28.7 years compared to 20.7 years in cases with REE (p<0.001). Pericoronal translucencies were found in four M(3), of which three were associated with SCE. Distal translucencies were found in 47 M(3), of which 15 were associated with SCE and inflammation. The prevalence was 2% for DC and 10% for IPC.

CONCLUSIONS

A differentiated application of histological and radiological criteria enables the prevalence of cystic lesions to be more accurately determined than does the use of one criterion alone.

Mucous and ciliated cell metaplasia in epithelial linings of odontogenic inflammatory and developmental cysts

The incidence of mucous and ciliated cells in epithelial linings was examined among odontogenic inflammatory cysts (radicular cysts) and developmental cysts (dentigerous and primordial cysts). Mucous cells were found in 20.8% of all cysts examined, while ciliated cells were found in 11.4%; however, ciliated cells were always accompanied by mucous cells. The incidence of mucous cells in radicular cysts and dentigerous cysts and that of ciliated cells in radicular cysts was higher in the maxilla than in the mandible, while the incidence of mucous cells in primordial cysts and that of ciliated cells in dentigerous cysts and primordial cysts was higher in the mandible than in the maxilla. The present results regarding mucous cells and ciliated cells in the epithelial linings of intraosseous odontogenic cysts indicate a metaplasic origin, but the cause and biological significance of this phenomenon is not known. Mucous cells were present in the surface layer of epithelial linings, and intraepithelial gland-like structures lined with mucous cells were observed in the hyperplastic regions of epithelial linings of several radicular and dentigerous cysts. Such gland-like structures lined by mucous cells in the thickened epithelial lining, which have not been demonstrated previously, resembled the glandular structures of "glandular odontogenic cysts".

Inverted central incisor--a case report

An unusual case of inverted central incisor in a nine year old girl is reported here. The case was diagnosed as an infected dentigerous cyst. The unerupted central incisor was placed inverted almost near the ethmoid bone. The cyst was enucleated successfully.

Upper lip swelling caused by a large dentigerous cyst

Swelling of the upper lip can result from various diseases such as salivary tumors, infectious and inflammatory diseases and cysts. Among the latter, dentigerous cysts, typically involving unerupted teeth, are sometimes associated with supernumerary teeth in the maxillary anterior incisors region called the mesiodens. We report an unusual case of a large dentigerous cyst associated with an impacted mesiodens in a 42-year-old male who presented with a slow-growing swelling in the upper lip.

A comparative study of epithelial cell proliferation between the odontogenic keratocyst, orthokeratinized odontogenic cyst, dentigerous cyst, and ameloblastoma

OBJECTIVES

The aim of the present study was to compare the proliferation index of the epithelial cells between odontogenic keratocysts (OKC), orthokeratinized odontogenic cysts (OOC), dentigerous cysts (DC), and ameloblastomas.

MATERIALS AND METHODS

The proliferation index, employing a novel cell proliferation marker IPO-38, was studied by the immunohistochemical technique in 10 OKC, seven OOC, eight DC and 10 ameloblastomas.

RESULTS

The ameloblastoma had no higher labeling index (LI) of IPO-38 than the OKC (P = 0.910) but had higher LI than the OOC (P = 0.001) and DC (P = 0.000); the OKC had higher LI than the OOC (P = 0.002) and DC (P = 0.000); and the OOC had higher LI than the DC (P = 0.011). IPO-38-positive cells in the OKC and OOC were located principally in the suprabasal cell layers while the ameloblastoma were found in the peripheral portion in particularly, the follicular and plexiform types.

CONCLUSION

These findings support previous studies that the proliferation indices are useful in predicting the different biological behavior of the odontogenic lesions and the OKC should be regarded as a benign tumor rather than simply an odontogenic cyst.

Parathyroid hormone-related protein (PTHrP) expression in ameloblastoma

OBJECTIVE

Parathyroid hormone-related protein (PTHrP) production has been demonstrated in a variety of tumor subtypes. Local production of PTHrP by metastatic tumor cells in bone has been linked to bone destruction and tumor growth. Ameloblastoma (AB) is a relatively common odontogenic epithelial neoplasm that manifests local infiltrative intraosseous growth. AB recapitulates the developing enamel epithelium, in which PTHrP recently has been demonstrated. Yet PTHrP expression in a series of ABs has not been studied to date. The purpose of this investigation is to assess the expression of PTHrP in ameloblastoma.

STUDY DESIGN

Formalin-fixed, paraffin-embedded tissue sections of ameloblastoma (n = 30; 24 conventional, 4 unicystic, and 2 arising in dentigerous cyst) were immunostained with anti-PTHrP antibody using a multistep streptavidin-peroxidase technique. Semiquantitative scoring of immunoreactivity was assessed as mild, moderate, and intense.

RESULTS

All cases (100%) demonstrated positive immunoreactivity, with mild reaction in 3 conventional ABs, 1 unicystic and 1 AB arising in dentigerous cyst, and with moderate reaction in 12 conventional ABs, 3 unicystic and 1 AB arising in dentigerous cyst. Intense immunoreactivity was seen in 9 cases of conventional AB. This difference in immunostaining was not statistically significant (Sigma2 = 4.41, df = 4, P = .358).

CONCLUSION

The results of this investigation suggest that PTHrP may play a significant role in local bone resorption, offering at least partial explanation for the tumor's infiltrative growth and destructive behavior. The uniformity of PTHrP expression by AB, as detailed in this study, may harbor significant therapeutic implications, particularly through PTHrP-blocking treatment modalities.

Clinical conditions for eruption of maxillary canines and mandibular premolars associated with dentigerous cysts

The aim of this study was to investigate the eruption of teeth associated with dentigerous cysts in the mandibular premolar and maxillary canine regions in preadolescents. Fifty-eight cyst-associated teeth, including 47 mandibular premolars and 11 maxillary canines, were examined retrospectively by using normalized panoramic radiographs and histological materials. The subjects were divided into 2 groups: the erupted group, in which the teeth had erupted successfully after marsupialization, and the nonerupted group, in which the teeth had undergone orthodontic traction or cystectomy with removal of the cyst-associated tooth. Eighty-one percent of the mandibular premolars and 36% of the maxillary canines in the cysts erupted successfully about 100 days after marsupialization without traction. The eruption of a mandibular premolar was significantly related to a shallow position in the alveolar bone, shallow angulation of the tooth, and young age of the patient but not to cyst size and dental space for the eruption. The eruption of the maxillary canine was significantly related to the small size of the cyst and the patient's age. The cyst walls of the erupted group showed severe inflammatory cellular infiltration. These findings present a treatment guideline for dentigerous cysts associated with mandibular premolars and maxillary canines in preadolescents.

Dentigerous cyst versus unicystic ameloblastoma--differential diagnosis in routine histology

BACKGROUND

Unicystic ameloblastomas (UAs) and dentigerous cysts (DCs) have an identical clinical and radiographic appearance. Some subtypes of UAs have a better prognosis than solid or multicystic ameloblastomas, and simple enucleation is the adequate treatment. The present study was designed to test the hypothesis that UAs with small islands of ameloblastomatous epithelium may be misdiagnosed as a DC or keratocyst if no more than two histologic sections are examined.

METHODS

A total of 101 resection specimens from 22 women and 73 men (mean age: 46.5 years) were selected, all showing the clinical and radiographic features of a DC. Only cysts with a minimum diameter of 15 mm in the panoramic X-ray were considered for the present investigation. The histopathologic diagnosis had been routinely established by examining two sections. For our study, the specimens were investigated by step sections at 50 microm and by staining of 5 microm thin sections with hematoxylin and eosin (H&E) at 1 mm levels. An average of 15 slides were evaluated per case.

RESULTS

Microscopic examination of the step sections did not reveal ameloblastomatous epithelium in the cyst lining epithelium of the 101 cases. Thus, every primary diagnosis of a dentigerous cyst was confirmed. In four cases, additional rather large odentogenic cell nests were detected with palisading of basaloid cells, while there was a lack of other signs of ameloblastic differentiation. All lesions were completely resected, and no additional treatment was performed.

CONCLUSIONS

Step sectioning of larger DCs may reveal associated odontogenic cell nests in some cases but does not lead to the detection of formerly missed ameloblastic cells. Thus, unicystic ameloblastomas are not misdiagnosed if only two slides are prepared for routine diagnosis of DCs.

Bilateral maxillary dentigerous cysts: a case report

Dentigerous cysts are benign odontogenic cysts that are associated with the crowns of permanent teeth. They are usually single in occurrence and located in the mandible. Multiple cysts are reported in patients with conditions such as mucopolysaccharidosis and basal cell nevus syndrome. We present the radiologic findings of bilateral impacted maxillary cuspids with dentigerous cysts displacing the maxillary sinuses in a nonsyndromic patient, a condition that, to our knowledge, has not been previously reported.

Maxillary dentigerous cyst in a cat

A dentigerous cyst was diagnosed in the right rostral maxilla of a 6-month-old Siamese cat affecting the maxillary right canine tooth. The deciduous maxillary right canine tooth was extracted and the dentigerous cyst wall was curetted. The permanent tooth was not removed, however it was mobile following the surgical procedure. Examination 6-months following surgery indicated appropriate development of the tooth with no mobility or periodontal pocket formation. The maxillary right canine tooth had an abnormal shape but was functional with an acceptable appearance.

Squamous cell carcinoma arising in a dentigerous cyst in a 16-month-old girl

Squamous cell carcinoma arising in a dentigerous cyst is a rare lesion with distinct histopathology and stringent criteria for diagnosis.(1,2) During the past century, <60 cases have been reported.(3) Of the previously documented cases, all have occurred in adults. We present the case of a squamous cell carcinoma arising in a dentigerous cyst in a 16-month-old girl. This case poses interesting questions regarding the pathophysiology of these tumors and highlights the importance of maintaining a high index of suspicion regardless of age when evaluating cystic lesions of the mandible and maxilla.

CD1a-positive cells in odontogenic cysts

Langerhans cells (LC) are bone marrow-derived cells that have a CD1a-positive immunophenotype and are an important portion of the cell-mediated immune response. The aim of this study was an immunohistochemical evaluation of CD1a positive cells in different types of oral cysts. Fifty-five cysts were studied: 18 odontogenic keratocysts (OKC), of which five were orthokeratotic and 13 parakeratotic; 19 radicular cysts; and 18 dentigerous cysts. Positive LC was 80% for orthokeratotic OKC, 33% for parakeratotic OKC, approximately 35% for radicular cysts, and approximately 20% for dentigerous cysts. The results show that OKC with well-differentiated epithelial linings presented a greater number of LC than the other cysts. However, when the cyst wall was inflamed there were no differences in LC expression in the different types of cysts. The data confirm that LC distribution seems to be associated with the degree of differentiation of the epithelia.

Ki-67 expression in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising from dental cysts

This study investigated whether or not an ameloblastoma developing in the wall of a dentigerous cyst is a distinct lesion from the unicystic ameloblastoma. An immunohistochemical evaluation of Ki-67 in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising in dentigerous cysts was done. The values of Ki-67 positivity were 3.14 for the dentigerous cyst, between 5.32 and 16.56 for unicystic ameloblastoma, and 11.77 for ameloblastoma arising in a dentigerous cyst. Statistically significant differences were found between the dentigerous cyst and the unicystic ameloblastoma and between the dentigerous cyst and the ameloblastoma arising from a dentigerous cyst. No statistically significant difference was present between unicystic ameloblastoma and ameloblastoma arising from dentigerous cyst. These immunohistochemical data confirm the hypothesis that an ameloblastoma arising from a dentigerous cyst has a similar biological behavior to the unicystic ameloblastoma and should be considered as merely a histologic variant.

Bilateral mandibular cysts associated with cyclosporine use: a case report

Cyclosporin A (CsA) is used in the treatment of patients undergoing renal transplantation. There are a number of side effects associated with its use. In particular, the gingival overgrowth represents the most important in the oral cavity. The authors present a case of bilateral mandibular cysts in an 8-year-old boy, treated with CsA after renal transplantation. The genesis of the mandibular cysts might be associated with the combined use of CsA and a calcium channel blocker post-transplantation. CsA-induced gingival overgrowth might contribute to cysts by two mechanisms: interference with control mechanisms that regulate the reabsorption of gingival stromal tissue, allowing progressive dental eruption, and an increase in the gingival connective tissue components. Gingival hypertrophy might mechanically obstruct the eruption of the developing tooth.