The odontogenic keratocyst: orthokeratinized variant

The histopathologic and clinical features of sixty cases of orthokeratinized odontogenic cysts were compared with those of odontogenic keratocysts (typically parakeratinized). According to the results of this study, the orthokeratinized odontogenic cyst appears to be a distinct clinicopathologic entity. This cyst is histologically characterized by a thin, uniform, epithelial lining with orthokeratinization and a subjacent granular cell layer. The basal cells are usually cuboidal or flattened. Clinically, the orthokeratinized cyst is a single cyst, shows a predilection for males, and is most often found in the second to the fifth decade, it appears most commonly as a dentigerous cyst in the posterior mandible. The orthokeratinized cyst shows little clinical aggressiveness. Follow-up of twenty-four patients revealed only one recurrence; of nineteen patients evaluated, none had features of the basal cell nevus-bifid rib syndrome. It is suggested that this cyst be called odontogenic keratocyst, orthokeratinized variant.     

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 ctinko-pathological entities different from odontogenic keralocysts 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.     

Calretinin expression in odontogenic cysts

Calretinin is a calcium-binding protein with a possible role as a calcium buffer, calcium-sensor, or regulator of apoptosis. Calretinin is expressed in neural tissue, is a specific marker of mesothelial cells, and has been demonstrated in the odontogenic epithelium during odontogenesis in rat molar tooth germs. Moreover, it has been found to be expressed in a high proportion of solid, unicystic, and multicystic ameloblastomas, whereas, on the contrary, no positive staining has been found in odontogenic keratocysts, residual cysts, and dentigerous cysts. The purpose of this study was to evaluate calretinin expression in radicular cysts, follicular cysts, orthokeratinized keratocysts, and parakeratinized keratocysts. A total of 70 odontogenic cysts, 24 radicular cysts, 24 follicular cysts, and 22 odontogenic keratocysts (10 orthokeratinized keratocysts, 12 parakeratinized keratocysts) were evaluated. All the radicular cysts, follicular cysts, and orthokeratinized keratocysts were negative. However in 8 of 12 parakeratinized keratocysts, there was a positivity to calretinin in the parabasal-intermediate layers of the cyst epithelium. This positivity to calretinin in the parabasal layers in parakeratinized keratocysts, similar to that found for other markers like PCNA and p53, could point to an abnormal control of the cell cycle and could help to explain the differences in the clinical and pathologic behavior of odontogenic keratocysts, in particular the differences found between orthokeratinized keratocysts and parakeratinized keratocysts.     

Dental lamina as presumptive source of odontogenic cyst

The possibility of the dental lamina as a source of odontogenic cyst was investigated. The mandibular first molar tooth germs with the dental lamina and surface oral epithelium were cut from 17.5-day-old C3H mouse embryos. The following 5 kinds of grafts were prepared: (I) recombinant of the dental lamina and dental papilla, (II) dental lamina, (III) dental papilla, (IV) recombinant of the oral epithelium and dental papilla and (V) oral epithelium. After the renal subcapsular transplantation to the 3-month-old syngenic male mice, each graft was harvested at timed sequences from 2 to 24 weeks and was examined histopathologically. The recombinant of the dental lamina and dental papilla (1) grew into a cyst lined by para-keratinized stratified squamous epithelium. The cyst enlarged gradually and might be compared to the odontogenic keratocyst of the human being. The recombinant of the oral epithelium and dental papilla (IV) and the oral epithelium (V) developed into a cyst lined by orthokeratinized stratified squamous epithelium which differed from the epithelium seen in Experiment (I). The dental papilla (III) grew to be a bone tissue while nothing developed from the dental lamina (II). These results suggest that the dental lamina is one of the sources of the odontogenic keratocyst and the dental papilla plays an important role in its histogenesis.     

The odontogenic keratocyst. A clinicopathologic study of 312 cases. Part I. Clinical features.

An analysis was made of the clinical features of 312 acceptable cases of odontogenic keratocysts from the files of the Department of Oral Pathology, Indiana University School of Dentistry. A total of 5.1 per cent of the keratocysts were from patients with the basal-cell nevus syndrome and 5.8 per cent were from patients with multiple keratocysts but with no other features of the syndrome. There was a wide age range, with a peak incidence in the second and third decades of life. The mandible: maxilla ratio was 2:1, with the mandibular third molar area and ramus being the most common sites. Dentigerous cyst was the most frequent clinical as well as histologic diagnosis for the majority of the keratocysts in this study. The primordial cyst comprised the greatest percentage of keratocysts (44.4 per cent). A total of 50.3 per cent of the patients were symptomatic before seeking treatment, the most common finding being intraoral drainage and swelling. Their radiographic appearance was quite variable, although they frequently resembled ameloblastoma. These cysts may be very aggressive clinically. They have a relatively high recurrence rate, as previously reported in the literature, in comparison with other types of odontogenic cyst. The findings in this study support the theory that the histologic appearance of an odontogenic keratocyst may be assumed by any of the odontogenic or nonodontogenic cysts.     

Correlation of lining thickness and expression of alpha 2 and alpha 3 integrins within the epithelial lining of odontogenic cysts.

Using monoclonal antibodies, we performed immunohistochemical investigations of the expression of alpha 2, alpha 3 and beta 4 integrin subunits within the squamous epithelial linings of odontogenic cysts. Tissue samples consisted of both follicular cysts and odontogenic keratocysts from 15 patients. It was found that beta 4 integrin was expressed on the basement membrane regardless of the histological type of the cyst. The degree of immunostaining for alpha 2 and alpha 3 integrin expression corresponded to the thickness of the epithelial cyst wall. We found that the thickness of the epithelial lining of odontogenic cysts had a direct correlation with the expression of integrin molecules.     

Inflammatory paradental cysts in the globulomaxillary region

Cysts located in the maxilla between the roots of an erupted lateral incisor and a canine were studied. Radicular cysts were excluded by the prerequisite of a positive pulp vitality test in both adjacent teeth, and odontogenic keratocysts were excluded by histologic examination. In the period from 1971-1987, 8 cysts were found which fulfilled the criteria for inclusion. The average age of the patients was 18.8 yr. All cysts were lined by a hyperplastic non-keratinized stratified squamous epithelium and there was always a heavy infiltrate of inflammatory cells in the connective tissue. The clinical and histologic features were similar to those previously reported for inflammatory paradental cysts (IPC) in the mandible. Therefore, it seems justified to suggest that some of the previously described globulomaxillary cysts are in fact IPCs.     

Cell proliferation markers in the odontogenic keratocyst: effect of inflammation

The immunohistochemical expression of PCNA and Ki-67 proteins and the histochemical expression of AgNORs were studied in 20 odontogenic keratocysts in order to assess the relationship between epithelial cell proliferation and inflammation within the capsule. Immunostained cells were quantified by conventional methods, and both quantitative and morphometric analyses of AgNORs were performed by TV image analysis. Non-inflamed odontogenic keratocysts showed a typical epithelial lining and inflamed odontogenic keratocysts were lined also by hyperplastic non-keratinized stratified squamous epithelium. A statistically significant increase of PCNA+ and Ki-67+ cells and of AgNOR numbers was detected in the linings of inflamed odontogenic keratocysts compared to non-inflamed lesions. The results suggest the existence of greater proliferative activity in the epithelial cells of inflamed odontogenic keratocysts, which may be associated with the disruption of the typical structure of odontogenic keratocyst linings.     

正角化牙源性囊肿的临床病理及免疫组化研究

目的：探讨一组正角化牙源性囊肿（orthokeratinized odontogenic cyst,OOC)的临床病理及免疫组化特点。方法：以OOC的名称报告20例，观察其组织学和免疫组化特点，并与牙源性角化囊肿（odontogenic keratocyst,OKC)病变进行比较。结果：本组病例约占同期所有OKC的9．9％（20／202），其中男性14例，女性6例，就诊平均年龄39．1％；随访资料显示：15例患者行囊肿刮治后无复发；组织学和免疫组化比较发现：OOC和OKC之间差异有显著性，OOC上皮不表现OKC上皮的形态分化特点，细胞增殖活性较低。结论：OOC可能代表一组有别于牙源性角化囊肿的颌骨病损。     

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".     

Odontogenic cysts: a clinical study of 90 cases

The maxillofacial region is affected by a greater number of cysts than any other part of the body. In this study, 90 odontogenic cysts were collected from 90 patients over a five-year period. Patients with radicular cysts, dentigerous cysts and odontogenic keratocysts were further analyzed with regard to age, sex and anatomical distribution. Using the histological classification of the World Health Organization, 53 cases (59%) were classified as radicular cysts, 24 (27%) as keratocysts and 13 (14%) as dentigerous cysts. Radicular cysts occurred most frequently in the anterior region of the maxilla, odontogenic keratocysts in the ramus and angular region of the mandible, and dentigerous cysts in the mandible. No recurrences were observed during the limited follow-up period.     

牙源性囊肿上皮增殖活性的研究

目的：研究牙源性角化囊肿,含牙囊肿,根尖囊肿3种主要的牙源性囊肿衬里上皮的细胞增殖活性,方法：应用Ki-67单克隆抗体免疫组化LSAB法对30例牙源性囊肿进行免疫组化染色,结果通过计算机图像分析,计算单位面积衬里上皮内（mm2)阳性细胞数,进行统计学分析,结果：牙源性角化囊肿衬里上皮有较多的Ki-67阳性细胞,明显高于含牙囊肿和根尖囊肿;正常口腔粘膜未见Ki-67阳性表达,结论：Ki-67在不同的牙源性囊肿中表达的差异显示了它们具有不同的增殖和分化过程。     

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.     

KAI-1 protein expression in odontogenic cysts

The KAI-1 tumor suppressor gene is widely distributed in normal tissues and its down-regulation may be correlated with the invasive phenotype and metastases in several different epithelial tumors. The aim of the present study was an evaluation of KAI-1 expression in radicular cysts (RC), follicular cysts (FC), orthokeratinized keratocysts (OOKC), and parakeratinized keratocysts (POKC). Eighty-five odontogenic cysts, 28 RC, 22 FC, and 35 OKC (16 OOKC, 19 POKC) were selected. All the POKC were negative and only four of 16 of the OOKC were positive for KAI-1. On the contrary, all RC and FC cases were positive and immunoreactivity for KAI-1 was detected throughout all the layers of the cyst epithelium. The lack of KAI-1 expression in POKC could help to explain the differences in the clinical and pathologic behavior of OKC and, according to what has been reported for epithelial tumors, could be related to the increased aggressive behavior and invasiveness of OKC.     

Scanning electron microscopy of odontogenic cyst epithelium.

The epithelial lining of 8 odontogenic keratocysts (OKC), 9 radicular (RC) and 3 dentigerous cysts (DC) were examined in SEM in order to study the ultrastructural surface topography of the lumenal surface cells. The orthokeratinized OKC showed a reticular network of intercommunicating microridges surrounding micropits giving a honeycombed appearance to the entire surface. The deep surface of these cells was covered by a complementary array of short stubby microvilli. This pattern was identical to that described for oral epithelium in areas of masticatory mucosa. The parakeratinized OKC showed a complex pattern of microplications (MP) on both upper and deep cell surfaces. The non-keratinized linings of RC and DC revealed a similar MP pattern but of a less complex nature. The MP pattern of cells from para- and non-keratinized cysts was identical to that described for oral epithelial cells from lining mucosa. The surface ultrastructure of ciliated, mucus and brush cells occurring in RC was found to be indistinguishable from that described in the mammalian respiratory tract. The MP pattern forms part of the cellular interdigitation mechanisms in stratified squamous epithelium. Differences in the ultrastructural configuration are related to the type of epithelium in terms of keratinization rather than to protective functions.     

Treatment of odontogenic keratocysts: a follow-up of 255 Chinese patients

OBJECTIVE: The purpose of this study was to report our experience in the surgical treatment of 484 Chinese patients with follow-up in 255 cases. METHODS: A retrospective analysis was conducted of all odontogenic keratocysts that were surgically treated and histopathologically diagnosed between 1962 and 1998. The odontogenic keratocysts were surgically treated with enucleation, marsupialization followed by secondary enucleation, and resection with or without continuity defects. The recurrence rate was evaluated for the patients followed more than 3 years. RESULTS: Of a total of 489 odontogenic keratocysts, 327 (66.87%) were found in the mandible and 162 (33.13%) in the maxilla. Follow-up data were obtained in 255 patients. Recurrence was found in 31 cases (15.27%) in 203 patients treated with enucleation after an observation period of 3 to 29 years. Twenty-nine recurrences (17.79%) were found in 163 patients treated with enucleation alone, two recurrences (6.70%) were seen in 29 patients who received Carnoy's solution fixation of the cyst wall before enucleation, and no recurrence was found in 11 cases treated with marsupialization in combination with secondary enucleation. No recurrence was seen in 52 patients treated with resection. CONCLUSION: Odontogenic keratocysts treated with enucleation alone have a higher recurrence rate. Enucleation with adjunctive treatment can decrease recurrence rate. Radical excision has no recurrence but does have the highest morbidity rate and should be reserved for multiple recurrent cysts after conservative means.     

牙源性角化囊肿细胞增殖抗原和表皮生长因子受体表达

目的　探讨牙源性角化囊肿衬里上皮细胞的增殖特点。方法　采用免疫组化染色方法 ,对牙源性角化囊肿、成釉细胞瘤、含牙囊肿、正常口腔粘膜上皮中细胞增殖抗原 Ki- 6 7和表皮生长因子受体 (EGFR)的表达进行分析比较。结果　牙源性角化囊肿中 Ki- 6 7表达较含牙囊肿高 ,与正常口腔上皮相似 ;复发的与未复发的牙源性角化囊肿 Ki- 6 7指数无显著性差异。牙源性角化囊肿中 EGFR表达呈阳性。结论　牙源性角化囊肿上皮增殖活跃 ,上皮增殖生长可能与表皮生长因子家族有关。     

Primary intraosseous odontogenic carcinoma arising in an odontogenic cyst or de novo: a clinicopathologic study of six new cases

The term primary intraosseous odontogenic carcinoma (PIOC) has been primarily used to describe a squamous cell carcinoma within the jaws arising either from a previous odontogenic cyst or de novo. Here, we report 6 new cases of PIOC, affecting 4 female and 2 male patients with a mean age of 56.2 years. Two cases involved the maxilla and 4 cases occurred in the mandible. The typical radiographic presentation was that of a radiolucent lesion with well or ill defined margins. Histopathologically, 4 cases were diagnosed as well differentiated keratinizing PIOC arising from previous odontogenic cysts (2 odontogenic keratocysts and 2 periapical cysts). The remaining 2 cases were poorly differentiated nonkeratinizing PIOC, which appeared to arise de novo. Treatment consisted of surgical removal, with postoperative radiotherapy in 5 cases, and to date neither recurrence nor metastasis have occurred. Knowledge of the clinical, radiographic, and histopathologic features of PIOC allows accurate diagnosis and appropriate treatment of this rare malignancy.     

Metaplasia and degeneration in odontogenic cysts in man

Abstract. In a histologic study of the walls of 638 odontogenic cysts, the incidence of metaplastic and/or degenerative changes was recorded. There were 402 denial cysts, 81 dentigerous cysts, 15 lateral periodontal cysts, 1 gingival cyst and 139 odontogenic keratocysts.
Mucus cells were present in 39.6 % of the dental cysts, 42.0 % of the dentigeious cysts, 20.0 % of the lateral periodontal cysts and 3.7 % of the odontogenic keratocysts. There was no difference in incidence between the maxilla and mandible. The incidence of mucus cells increased with the age of the patient from whom the cyst was removed. Ciliated cells were present in 0.7 % of the dental cysts and 1.5 % of the odontogenic keratocysts, but were absent from dentigerous cysts and lateral periodontal cysts. Keratin was present in 2.0 % of the dental cysts, 2.5 % of the dentigerous cysts, and all of the odontogenic keratocysts, but was absent from lateral periodontal cysts. Hyaline bodies were present in 6.7 % of the dental cysts, 1.2 % of the dentigerous cysts, none of the lateral periodontal cysts and 9.4 % of the odontogenic keratocysts. Mineralized bodies were present in 2.5 % of the dental cysts, 7.4 % of the dentigerous cysts, 6.7 % of the lateral periodontal cysts and 12.9 % of the odontogenic keratocysts. The origin of these changes is discussed in the light of these findings.     

Range and demographics of odontogenic cysts diagnosed in a UK population over a 30-year period

BACKGROUND: The aim of this study was to determine the range of all histologically diagnosed odontogenic cysts along with age range, sex distribution and site of presentation over a 30-year period. METHODS: All entries for odontogenic cysts occurring during 1975-2004 inclusive were retrieved and analysed for demographic data. RESULTS: A total of 55,446 specimens were received, of these 7121 (12.8%) specimens were diagnosed as odontogenic cysts. Radicular cyst was the most common diagnosis (52.3%), followed by dentigerous cyst (18.1) and odontogenic keratocysts (11.6%). CONCLUSIONS: Our study provides demographic data on a large series of odontogenic cysts in a European population. This is one of the largest series reported to date. Cysts such as the paradental cyst have a predilection for certain ages, sexes and sites. Odontogenic keratocysts and glandular odontogenic cysts have a marked propensity to recur as well as behave aggressively. It is essential that such lesions are detected as early as possible to minimize any necessary surgery.