Orthokeratinised odontogenic keratocysts in Malaysians

How reliable are follow-up studies on odontogenic keratocysts?

Follow-up studies on odontogenic keratocysts have reported widely varying recurrence rates. This raises the question of how reliable these studies are and how the results should be interpreted. The aim of this study was to critically assess the information from all follow-up studies published since 2004 against a set of criteria to determine how thorough the study was. These criteria include the exclusion of the orthokeratinized variant, exclusion of cysts associated with nevoid basal cell carcinoma syndrome, and appropriate reporting of dropouts. A search of four electronic databases covering the years 2004-2022 was performed. Only studies with a sufficient follow-up period (covering a range of 1-8 years) were included. Studies with fewer than 40 cases were excluded. Fourteen relevant studies were identified in the literature search. The vast majority of these studies had considerable shortcomings, giving rise to serious doubts about the validity of their recurrence rate results. Of note, these studies have often been included in meta-analyses that report on the best treatment options to reduce the tendency of recurrences. The results of this review strongly suggest that multicentre studies with strict protocols should be performed to advance knowledge of the presentation of recurrences, both the timing and frequency.

Orthokeratinized odontogenic cysts: A clinicopathologic study of 159 cases and molecular evidence for the absence of PTCH1 mutations

BACKGROUND

Orthokeratinized odontogenic cyst (OOC), a newly designated entity of odontogenic cysts, is an intraosseous jaw cyst that is entirely or predominantly lined by orthokeratinized squamous epithelium. The aim of this study was to report a large series of OOC to substantiate its clinicopathologic profiles and to investigate PTCH1 mutations in OOCs.

METHOD

The clinicopathologic features of 167 OOCs from 159 patients were analyzed and the immunohistochemical expression of markers related to cell differentiation and proliferation was evaluated. Furthermore, PTCH1 mutations were analyzed in 14 fresh samples of OOC.

RESULTS

OOCs occurred mostly in the third and fourth decades (60.4%) with a male predilection (66.7%). The lesions developed more often in the mandible than maxilla, primarily in the posterior mandible and ramus. Eight patients (5.0%) showed multiple locations of either bilateral posterior mandible (n = 6) or both the maxilla and mandible. Radiographically, the majority of OOCs (91.2%) showed a well-demarcated, unilocular radiolucency with 14 multilocular cases (8.8%). A follow-up of 131 patients (123 treated by enucleation with or without marsupialization and eight by peripheral ostectomy) revealed no recurrence during an average period of 4.56 years after surgery. Immunohistochemistry indicated lower proliferative activity and a varying epithelial differentiation pattern in OOC compared with odontogenic keratocysts (OKC). No PTCH1 mutation was detected, except for three known single nucleotide polymorphisms.

CONCLUSION

The clinicopathological and molecular differences between OOC and OKC justified their separation, and unlike OKCs, OOCs did not harbor PTCH1 mutations, suggesting different pathogenesis underlying these two jaw cysts.

The Clinical Features and Expression of bcl-2, Cyclin D1, p53, and Proliferating Cell Nuclear Antigen in Syndromic and Nonsyndromic Keratocystic Odontogenic Tumor

The aim of this study was to describe the clinical features and expression of bcl-2, cyclin D1, p53, and proliferating cell nuclear antigen (PCNA) antibodies in syndromic (nevoid basal cell carcinoma syndrome [NBCCS]) and nonsyndromic patients diagnosed with keratocystic odontogenic tumor (KCOT).

METHODS

This descriptive study comprised 5 patients of KCOT associated with NBCCS and 8 patients of nonsyndromic type treated in the Department of Oral Maxillofacial Surgery, Universiti Kebangsaan Malaysia Medical Centre between years 1998 and 2011. The clinical features (site, size, treatment, and recurrence), demographic characteristics, and immunohistochemistry results using antibodies of bcl-2, cyclin D1, p53, and PCNA were examined. The association of the antibody expression and the type of KCOT was analyzed using Fisher exact test.

RESULTS

Altogether there were 13 patients, 5 with syndromic KCOT (1 patient met 3 major criteria of NBCCS) and 8 with sporadic KCOT. The age range for syndromic KCT was 11 to 21 years (mean 16.00 years, SD 4.36) and 10 to 54 years (median 24.50 years, interquartile range 19.00) for the nonsyndromic KCOT. Tumor recurrence occurred in 3 patients (7.7%); 1 patient from the syndromic and 2 patients from the nonsyndromic. The most positive expression was observed in PCNA for both the syndromic and nonsyndromic samples and the least positive expression involved the p53.

CONCLUSION

PCNA, bcl-2 protein, and cyclin D1 expressions could be useful in evaluating the proliferative activity of the tumor and the aggressiveness of the clinical presentation; however, the authors would propose for larger sample size research for more definitive results.

Comparative study of cytokeratin and langerin expression in keratinized cystic lesions of the oral and maxillofacial regions

Dermoid cysts (DMCs) and epidermoid cysts (EDMCs) usually arise in soft tissues, whereas orthokeratinized odontogenic cysts (OOCs) and keratocystic odontogenic tumors (KCOTs) develop in the jaw. In this study, we performed immunohistochemical analysis of cytokeratins (CKs) to examine differences in the lining epithelium of DMCs, EDMCs, OOCs, and KCOTs. In addition, we carried out immunohistochemical examination of langerin to clarify the biological characteristics of the orthokeratinized lining epithelium of DMCs, EDMCs, and OOCs. Seven DMCs, 30 EDMCs, 11 OOCs, and 28 KCOTs were examined immunohistochemically using antibodies against CK10, 13, 14, 16, 17, 19, and langerin. Immunoreactivities for CKs and langerin in oral DMCs and EDMCs were similar to those of lesions affecting the skin. Positive reactivity for CK13 and 17 was evident in OOCs, but not in DMCs/EDMCs. CK10 was significantly positive in all layers except for the basal layer in OOCs, but was negative in KCOTs. CK17 was positive in all layers in KCOTs, and in all layers except for the basal layer in both OOCs and dentigerous cysts. CK19 was negative in OOCs. Langerhans cells were found mainly in OOCs, but were hardly evident in KCOTs. These results suggest that DMCs/EDMCs, OOCs and KCOTs are independent diseases.

Claudin expression and tight junction protein localization in the lining epithelium of the keratocystic odontogenic tumors, dentigerous cysts, and radicular cysts

OBJECTIVE

The aim of this study was to evaluate the expression and localization of tight junction proteins (TJPs) or claudins in the keratocystic odontogenic tumor (KCOT) and to correlate with its biological behavior.

STUDY DESIGN

Five claudins (-1, -3, -4, -5, and 7) were examined immunohistochemically in 25 KCOTs and compared with 10 dentigerous cysts (DCs) and 10 radicular cysts (RCs).

RESULTS

Marked claudin-3 loss of expression in KCOT basal layer (n=24/25; 96%) compared with DCs (n=1/10; 10%) and RCs (n=5/10; 50%) (P<.05) suggests that claudin-3 downregulation may indicate altered or loss of basal cell polarity and impaired barrier function of KCOT lining epithelium and this might contribute indirectly to its biological behavior. In contrast, claudins-1, -4, -5, and -7 distribution patterns were less distinctive in all three entities, suggesting that these TJP molecules probably play limited roles in influencing their different growth potentials.

CONCLUSION

Present findings suggest that differential claudin expressions in the lining epithelium of KCOTs, DCs, and RCs probably reflect their neoplastic or nonneoplastic nature.

Notch signaling and ghost cell fate in the calcifying cystic odontogenic tumor

Notch signaling is an evolutionarily conserved mechanism that enables adjacent cells to adopt different fates. Ghost cells (GCs) are anucleate cells with homogeneous pale eosinophilic cytoplasm and very pale to clear central areas (previous nucleus sites). Although GCs are present in a variety of odontogenic lesions notably the calcifying cystic odontogenic tumor (GCOT), their nature and process of formation remains elusive. The aim of this study was to investigate the role of Notch signaling in the cell fate specification of GCs in CCOT. Immunohistochemical staining for four Notch receptors (Notch1, Notch2, Notch3 and Notch4) and three ligands (Jagged1, Jagged2 and Delta1) was performed on archival tissues of five CCOT cases. Level of positivity was quantified as negative (0), mild (+), moderate (2+) and strong (3+). Results revealed that GCs demonstrated overexpression for Notch1 and Jagged1 suggesting that Notch1Jagged1 signaling might serve as the main transduction mechanism in cell fate decision for GCs in CCOT. Protein localizations were largely membranous and/or cytoplasmic. Mineralized GCs also stained positive implicating that the calcification process might be associated with upregulation of these molecules. The other Notch receptors and ligands were weak to absent in GCs and tumoral epithelium. Stromal endothelium and fibroblasts were stained variably positive.

Orthokeratinized odontogenic cyst: a clinicopathologic study of 61 cases

CONTEXT

Orthokeratinized odontogenic cyst (OOC) is a relatively uncommon developmental cyst comprising about 10% of cases that had been previously coded as odontogenic keratocysts. Odontogenic keratocyst was designated as keratocystic odontogenic tumor (KCOT) in the new World Health Organization classification and OOC should be distinguished from KCOT for differences in histologic features and biologic behavior.

OBJECTIVE

To analyze the clinicopathologic features of 61 cases of OOC in a Chinese population.

DESIGN

Clinicopathologic analysis was performed on 61 cases of OOC. Immunohistochemical expression of Ki-67 and p63 was evaluated in 15 OOCs and 15 typical KCOTs.

RESULTS

The 61 patients with OOC ranged from 13 to 75 years (average, 38.93 years). The lesions developed mainly in the third and fourth decades (57.38%) with a distinct predilection for males (72.13%). Six (9.84%) lesions were found in the maxilla and 55 (90.16%) in the mandible. The most common sites were in the mandibular molar and ramus region. Of the 54 cases with radiographic record, 47 (87.04%) were unilocular and 7 (12.96%) were multilocular radiolucencies. Twenty-seven of the 54 cysts were associated with an impacted tooth. Follow-up of 42 patients revealed no recurrence during an average period of 76.8 months after surgery. Compared with KCOTs, expression level of Ki-67 and p63 was significantly lower in OOCs, suggesting a lower proliferative activity.

CONCLUSION

Orthokeratinized odontogenic cyst is clinicopathologically distinct from KCOT and should constitute its own clinical entity.

Gorlin's syndrome - Report of a case and management of cystic lesions

Gorlin's syndrome associated with multiple cystic lesions is a rare and uncommon condition. It is characterized by cutaneous basal cell carcinomas, multiple keratocysts in the jaw bones and skeletal anomalies. A case is presented with multiple odontogenic keratocyst and dentigerous cysts occurring in all quadrants of oral cavity with features suggestive of Gorlin's Syndrome. The clinical presentation and the management of these multiple cystic lesions and a two year follow up study is presented.

Orthokeratinized odontogenic cyst of the mandible with heterotopic cartilage

Cartilaginous metaplasia is a rare but well-documented phenomenon occurring in the wall of odontogenic keratocyst. The mural cartilage not associated with odontogenic keratocyst has been reported only once in a maxillary teratoid cyst of congenital origin to our knowledge. A case presented is a 38-year-old man with intraosseous keratinizing epidermoid cyst in the mandible, the wall of which contained a nodule of mature hyaline cartilage. The present lesion likely represents a previously undescribed, histologic hybrid consisting of orthokeratinized odontogenic cyst and cartilaginous heterotopia.

A review of odontogenic keratocysts and the behavior of recurrences

OBJECTIVE

The purpose of this study is to report experiences of odontogenic keratocysts (OKCs) and analyze information regarding recurrences to better understand the nature of recurrences.

STUDY DESIGN

Fifty-one cases of OKC treated at the Faculty of Dentistry, Chulalongkorn University, from 1988 to 2003 were studied retrospectively. Clinicoradiographic features, histologic features, and methods of treatment were reviewed. Recurrences were analyzed and compared with respect to sites of involvement, relationship to the remaining teeth, and methods of treatment.

RESULTS

OKCs occurred predominantly in the 11- to 40-year-old age group. The body-angle-ramus area of mandible was the most common site of occurrence. Radiographically, the unilocular to multilocular radiolucency ratio was 2.5:1. Multilocular lesions occurred more frequently in the mandible (P < .05). Most of the lesions were diagnosed histologically as parakeratinized OKC (93.7%). The patients were followed from 1-14.6 years. However, 20 patients were lost to follow-up after a short period of time, and recurrences were found in 7 out of 31 cases (22.6%). The recurrent tumors occurred more frequently in patients who had an OKC associated with the remaining teeth and were treated by enucleation or enucleation with adjuvant therapy.

CONCLUSIONS

According to a high recurrent rate of OKCs treated by enucleation, clinicians should give more attention to the dentate area if the enucleation is chosen as the treatment of choice.

Nevoid basal cell carcinoma syndrome: a review of the literature

The nevoid basal cell carcinoma syndrome (NBCCS) or Gorlin-Goltz Syndrome is an autosomal dominant disorder principally characterized by cutaneous basal cell carcinomas, multiple keratocysts, and skeletal anomalies. The present report reviews current knowledge of this disorder that has profound relevance to specialists in Oral and Maxillo-Facial Surgery, Oral Medicine and Radiology.

Immunohistochemical study of the orthokeratinized odontogenic cyst: a comparison with the odontogenic keratocyst

OBJECTIVE

Orthokeratinized odontogenic cyst (OOC) is a developmental cyst that occurs in the maxilla and the mandible and is defined by the World Health Organization as the uncommon orthokeratinized type of odontogenic keratocyst (OKC). However, studies have shown that OOC has peculiar clinicopathologic aspects and biologic behavior when compared with other developmental odontogenic cysts, especially OKCs. Therefore, in this study, the immunohistochemical profile of the OOC was delineated and compared with that of the OKC.

STUDY DESIGN

Twelve cases of OOC were submitted to a panel of antibodies composed of cytokeratins (10, 13, and 14) and extracellular matrix proteins: fibronectin, types I and III collagen, and tenascin. For comparative means, 12 cases of OKC also were submitted to the same panel of antibodies.

RESULTS

The results obtained showed that OOCs expressed cytokeratin 10 and showed variable expression of cytokeratins 13 and 14. Fibronectin and collagen types I and III also were expressed in OOC in a fibrillar aspect. OKC showed only the superficial keratin layer positive to cytokeratin 10 and the basal and suprabasal layers with variable expression of cytokeratin 14, and cytokeratin 13 was present in the upper epithelial layers. The extracellular matrix proteins showed a nonfibrillar expression. Tenascin was immunoexpressed only in OKC.

CONCLUSION

The immunohistochemical profile of the studied cysts clearly showed that OOC presents a well-formed cystic enveloping, whereas the OKC profile is compatible with a more aggressive biologic behavior.

The aggressive nature of the odontogenic keratocyst: is it a benign cystic neoplasm? Part 1. Clinical and early experimental evidence of aggressive behaviour

In this, the first of three articles on the aggressive nature of the odontogenic keratocyst (OKC), there is a review of clinical and histological observations which indicated that this was an aggressive lesion with a predilection for recurrence unlike the majority of other jaw cysts. This led to the tentative suggestion that the OKC might be a benign neoplasm. Subsequently there were early laboratory investigations that compared proliferation rates of the OKC epithelium with other jaw cysts, comparative enzyme histochemistry to assess aspects of its metabolism and markers that would enable accurate presurgical diagnosis of this cyst. Comparative studies were also pursued on the walls of the OKC and other jaw cysts to identify factors that might influence the capacity of the OKC to resorb the bone surrounding it. The clinical and laboratory studies reviewed in this section provided cogent presumptive evidence of the distinctively aggressive nature of the OKC that led numbers of investigators to pursue immunocytochemical and genetic studies on this cyst. Parts 2 and 3 of this series review this work.

Long-term follow-up on keratocysts treated according to a defined protocol

A prospective study was conducted on 82 odontogenic keratocysts (OKCs) diagnosed in 80 patients over a 25 year period. The clinical and radiographic data were correlated, which resulted in an accurate picture of the clinical presentation, relationship with teeth and incidence of lingual perforations in mandibular OKCs. In 40% of the cysts no suspicion had arisen before surgery, in 60% the diagnosis was secured before surgery. This last group of patients was treated according to a defined protocol, with the exception of the maxillary OKCs, which entailed excision of the attached, overlying mucosa and enucleation of the cyst after which the defect was treated with Carnoy's solution. The other patients underwent just enucleation of the cysts. For the first 5 years the patients were seen every year, thereafter every 2 years if possible. Recurrences (9/82) were mainly found in the patients in which the cyst had just been enucleated. Only three cysts recurred in the group treated according to the above mentioned protocol. Most recurrences presented within 5 years, but late recurrences did occur even after 25 years. The aetiology and pathogenesis of OKCs is briefly discussed in the light of the present findings. It is concluded that the suggested treatment protocol and follow-up schedule provides a safe means to manage a lesion that is known to recur and may even give rise to life threatening situations.

Orthokeratinized odontogenic cyst: a clinicopathological and immunocytochemical study of 15 cases

AIMS

Intraosseous jaw cysts with a solely orthokeratinized lining epithelium have been suggested to differ from the typical odontogenic keratocysts (OKC) by exhibiting a less aggressive behaviour. We report 15 cases of such cyst type under the term of 'orthokeratinized odontogenic cyst (OOC)' and compared their clinical, histological and immunocytochemical features with that of OKC.

METHODS AND RESULTS

The cysts of the present series were all solitary lesions, occurred mostly in young male patients, and showed a predilection for the posterior mandible areas. Follow-up of 14 patients, nine of whom were treated by simple enucleation, revealed no recurrence over a period of 3.5-12 years after surgery. None of the patients had any association with the naevoid basal cell carcinoma syndrome. Furthermore, histological and immunocytochemical comparison between OOC and OKC revealed marked differences in their morphology and epithelial expression. The lining epithelium of OOC lacked the typical features of OKC and appeared to show a lower proliferative activity.

CONCLUSION

These findings suggest that OOC is clinicopathologically separate from other types of odontogenic cysts and may thus constitute a distinct clinical entity.

Jaw cysts with orthokeratinization: analysis of 12 cases

The clinico-pathologic, immunohistochemical and radiological features of 12 jaw cysts with a prominent orthokeratinized epithelial lining were studied and compared with those of typical odontogenic keratocysts and dentigerous cysts. They differed significantly from odontogenic keratocysts in terms of biologic behavior and histopathologic findings. Although immunohistochemical staining of the epithelial linings for cytokeratins, EMA, CEA and involucrin has not shed any light on the histogenesis of these lesions, staining patterns for these markers were significantly different from those of odontogenic keratocysts and non-keratinized dentigerous cysts. Radiologically, nine cases appeared as dentigerous cysts; two cases, one with sebaceous differentiation, as non-dentigerous unilocular cysts, and the remaining one was exceptional as it showed multiple epidermal cysts with prominent dermal appendages histologically. It is suggested that most of the orthokeratinized jaw cysts may belong to clinico-pathological entities different from odontogenic keratocysts with the majority representing dentigerous cysts with orthokeratinization. The possibility of the existence of rare central dermoid or epidermoid cysts is also to be considered.

Odontogenic keratocysts: clinicopathologic study of 87 cases

The clinical and histologic features of 87 cases of odontogenic keratocysts were reviewed. Males were affected more frequently than females. All age groups were affected, with a predilection for the fifth and sixth decades. The molar-angle-ramus area of the mandible was the most common location (29.8%). In 7 cases (8.8%), the cysts were part of the basal cell nevus syndrome. Recurrences were observed in 9 cases (10.4%). The cysts were lined by a thin, regular, stratified squamous, parakeratinized epithelium without rete ridges. Orthokeratin was observed in 24.14% of the cases. Mitotic figures were observed in approximately 50% of the cases. Separation of lining epithelium from underlying connective tissue was observed in 82.7%, with subepithelial hyalinization in 75.8% of the cases. Inflammation was observed in 72.4%, cholesterol clefts were observed in 11.5%, and Rushton hyaline bodies in 4.6% of the cases. Dental lamina rests were observed in 32.2% and satellite cysts in 20.7%. Dystrophic calcifications were found in 36.8%. Ameloblastomatous proliferation was observed in 2 cases.