Vacuolated cells and mucous metaplasia in the epithelial linings of radicular and residual cysts

The purpose of this study was to determine whether a consistent association exists between mucous cells and clear or vacuolated cells in the epithelial lining of radicular and residual cysts and to consider whether the vacuolated cells may represent a stage in the histogenesis of mucous metaplasia in these linings. Single sections from each of 154 mandibular radicular and residual cysts were stained with periodic acid-Schiff (PAS) after diastase digestion. Fifteen cases which showed mucous metaplasia were included in the study and were examined for the presence of vacuolated cells associated with the mucous cells. Mucous cells were present singly or in groups within all layers of the stratified squamous epithelial lining except the basal cell layer. In nearly all instances small to large ovoid vacuolated cells were found closely associated with the mucous cells. Occasional vacuolated cells contained sparse mucin granules or a delicate network of PAS-positive, diastase-resistant material. It is suggested that the clear cells may represent a stage in the histogenesis of mucous metaplasia.     

Immunohistochemical study of jaw cysts: different existence of keratins in odontogenic and non-odontogenic epithelial linings

Keratins and secretory component (SC) were immunohistochemically examined in fresh tissue samples from 45 odontogenic and 35 non-odontogenic cysts. Lining epithelia of almost all cases contained keratins which reacted with polyclonal antibodies (Dako, Bio-Science), and no difference could be found between the two groups of lesions. By staining with two monoclonal antibodies against keratins, i.e., RGE53 (Bio-Science) and RKSE60 (Bio-Science), it was revealed that the epithelia of non-odontogenic cysts, which were columnar epithelium in most cases, had fully and positively reacted with RGE53, while none of the cases was positive for RKSE60. In contrast, the squamous linings of odontogenic cysts except for two cases did not react with RGE53, and few cases possessed RKSE60-reactive keratin. SC was also contradictory. All non-odontogenic cysts exhibited SC. Regarding each pair of non-odontogenic and odontogenic cysts covered with RGE53 and SC-positive, and RKSE60-negative squamous epithelium, it seemed reasonable from the staining results to conclude that the squamous linings were metaplastic from the columnar epithelium. Based on the results, concomitant examinations of SC with keratins will be helpful in deciding the epithelial derivation of jaw cysts.     

An immunocytochemical study of the inflammatory cell infiltrate and epithelial expression of HLA-DR in odontogenic cysts

The presence and distribution of lymphocytes, Langerhans cells, HLA-DR' infiltrating cells and the expression of HLA-DR by lining epithelium was investigated in the walls of odonlogenic cysts using an indirect immunoperoxidase method on acetone-fixed cryostat sections. The 23 cysts studied consisted of 14 dental (radicular) cysts, 5 keratocysts, 2 dentigerous cysts, 1 surgical ciliated cyst and 1 incisive canal cyst. The cell populations detected in the walls of all cysts were similar and consisted of HLA-DR+ macrophage-type cells and a mixture of T and B lymphocytes. Analysis of the T cell subsets revealed that in all cases the CD4⁺, T_h/i subset predominated over the CD8⁺, T_s/c subset. 18/22 cyst linings contained cells expressing a Langerhans cell phenotype (CD1⁺). Cytoplasmic epithelial expression of HLA-DR was detected in 7/22 specimens. Neither the presence of HLA-DR⁺ epithelial cells nor LC were restricted to a given type of cyst. These findings indicate the occurrence of similar cellular processes irrespective of the proposed developmental or inflammatory aetiology of these lesions.     

An immunocytochemical study of the inflammatory cell infiltrate and epithelial expression of HLA-DR in odontogenic cysts

The presence and distribution of lymphocytes, Langerhans cells, HLA-DR+ infiltrating cells and the expression of HLA-DR by lining epithelium was investigated in the walls of odontogenic cysts using an indirect immunoperoxidase method on acetone-fixed cryostat sections. The 23 cysts studied consisted of 14 dental (radicular) cysts, 5 keratocysts, 2 dentigerous cysts, 1 surgical ciliated cyst and 1 incisive canal cyst. The cell populations detected in the walls of all cysts were similar and consisted of HLA-DR+ macrophage-type cells and a mixture of T and B lymphocytes. Analysis of the T cell subsets revealed that in all cases the CD4+, Th/i subset predominated over the CD8+, Ts/c subset. 18/22 cyst linings contained cells expressing a Langerhans cell phenotype (CD1+). Cytoplasmic epithelial expression of HLA-DR was detected in 7/22 specimens. Neither the presence of HLA-DR+ epithelial cells nor LC were restricted to a given type of cyst. These findings indicate the occurrence of similar cellular processes irrespective of the proposed developmental or inflammatory aetiology of these lesions.     

Differences in in vitro growth of epithelium from inflammatory and developmental odontogenic cysts

Ninety-three odontogenic cysts, 42 of inflammatory and 51 of developmental origin, were grown in vitro from explants and/or cell suspensions. There was little difference in the success rate of culturing epithelium from explants of dentigerous cysts (N = 28) or odontogenic keratocysts (N = 23) (approximately 75% and 87%, respectively) and the dentigerous cyst grew particularly well from suspensions (N = 11) (91%) compared with the keratocyst (N = 19) (58%). Epithelium from developmental odontogenic cysts grew much better in vitro than did cysts of inflammatory origin (56 to 58% from explants and 19 to 25% from suspension). From this work there is little evidence to support previous statements that the dentigerous cyst cannot be grown from explants, or that the odontogenic keratocyst has 'aggressive' growth characteristics.     

Immunostaining of involucrin in odontogenic epithelial tumors and cysts

An immunoperoxidase method was used to detect involucrin in 47 odontogenic tumors and 35 radicular cysts. Of a total of 40 ameloblastomas, 9 cases were positive for involucrin expression and those positive cases exhibited acanthomatous or follicular patterns. Squamous odontogenic tumors were strongly positive for involucrin, whereas adenomatoid odontogenic tumors gave a negative staining reaction. Involucrin expression in odontogenic tumors was divided into three categories: single cell positive, focally positive, and squamous metaplastic cell positive. Radicular cysts showed a very irregular distribution of involucrin; nonstratified epithelium was generally negative or showed only trace staining for involucrin, whereas suprabasilar stratified squamous epithelial cells were strongly positive. Cells positive for involucrin in odontogenic tumors and in cystic epithelium are probably direct signs of epithelial differentiation; such cells were squamoid in appearance.     

The prevalence of inflammatory and developmental odontogenic cysts in a Jordanian population: a clinicopathologic study.

OBJECTIVE: To determine the prevalence of odontogenic jaw cysts in a Jordanian population and to compare these data with previously published reports from other geographic areas. METHOD AND MATERIALS: The files on odontogenic jaw cysts treated between 1989 and 2001 in the Oral and Maxillofacial Pathology Diagnosis Service at the Department of Oral Medicine and Oral Surgery, Faculty of Dentistry, Jordan University of Science and Technology, were reviewed. Clinical and radiographic data were recorded and microscopic slides evaluated according to the most recent World Health Organization classification. Cases were analyzed with regard to age, sex, and anatomic site. RESULTS: A diagnosis of odontogenic jaw cyst was established in 654 patients, with a male-to-female ratio of 1.7:1. Radicular cyst was the most common type of odontogenic cyst found (41.7%), followed by dentigerous cysts (24.8%). The peak age affected was between the third and fifth decades. Both jaws were almost equally affected. The most common anatomic site of incidence was the maxillary incisor/canine region, followed by the mandibular molar region. CONCLUSION: This study indicates that there are some geographic differences with regard to the relative frequency, sex, and anatomic distributions of odontogenic cysts.     

Evidence for a role of mitogen-activated protein kinases in proliferating and differentiating odontogenic epithelia of inflammatory and developmental cysts

OBJECTIVE: The activation of intracellular signaling cascades involving serine/threonine kinases ERK1/2 has been variably reported either to stimulate or inhibit epithelial cell differentiation in response to extracellular signals. The purpose of our study was to determine the distribution of the signaling molecule ERK1 and its activated form pERK1/2 in the epithelial components of developmental and inflammatory odontogenic cysts in relation to parameters of differentiation and proliferation. STUDY DESIGN: Thirty samples of dental follicles, dentigerous cysts, and radicular cysts were immunostained with antibodies to ERK1, pERK1/2, and proliferating cell nuclear antigen (a marker for proliferation). The tissues were subclassified according to the pattern of histomorphological differentiation (ie, squamous differentiation) and the proliferation rate of their epithelial components. The significance of differences in the proportion of ERK1- and pERK1/2-expressing cells among the tissue groups was determined by chi-square analysis or Fisher's exact test. RESULTS: ERK1 and pERK1/2 were found to be expressed in a significantly higher proportion of cells with differentiated and highly proliferating epithelial components, as compared with those of nondifferentiated, quiescent epithelial rests. The epithelium of radicular cysts exhibited the highest proportion of pERK1/2-positive cells. In both dentigerous and radicular cyst samples, pERK1/2 expression was significantly higher in the inflamed tissues. CONCLUSIONS: These data demonstrate that ERK1 and its active form pERK1/2 are associated with differentiating and actively proliferating epithelia of odontogenic cysts, and are consistent with pERK1/2 involvement in the activation of odontogenic epithelia in response to inflammation.     

Cytokeratin expression of the odontogenic epithelia in dental follicles and developmental cysts

The patterns of cytokeratin expression in the epithelium of 5 dental follicles, 7 dentigerous cysts, 5 odontogenic keratocysts, 3 nasopalatine cysts and an epidermoid cyst have been studies using a panel of monoclonal antibodies. The epithelium of dental follicles and of developmental odontogenic cysts strongly expressed keratins 5 and 19 and showed weaker expression of keratins typical of stratified non-cornified and of simple epithelia. Staining with mAbs against the latter keratins varied with the degree of epithelial differentiation. Nasopalatine cysts strongly expressed simple epithelial keratins and the epidermoid cyst strongly expressed a marker of cornification. Odontogenic cysts thus appear to differ in their pattern of keratin expression from other oral developmental cysts and all derivatives of odontogenic epithelia appear to share similar basic patterns of cytokeratin expression.     

Perlecan-rich epithelial linings as a background of proliferative potentials of keratocystic odontogenic tumor

Background:  The intraepithelial deposit of perlecan, a basement membrane-type heparan sulfate (HS) proteoglycan, has been demonstrated in neoplastic conditions such as salivary gland tumors, odontogenic tumors, and oral carcinoma in situ . Our aim was to determine whether perlecan turnover was enhanced in the lining cells of keratocystic odontogenic tumor (KCOT), which had been recently renamed from odontogenic keratocyst because of its accumulated evidence of neoplasm, as a possible background for neoplastic proliferation.
Methods:  Ten surgical specimens from each of KCOT, dentigerous cyst, and radicular cyst were examined for the expressions of perlecan core protein, HS chains, heparanase, and Ki-67 by immunohistochemistry and in situ hybridization.
Results:  In KCOT, perlecan core protein and HS chains were localized on the cell border from the parabasal to subkeratinized layers of the lining epithelium. Heparanase was localized in a similar fashion to those for perlecan and HS chains but was within the cytoplasm. mRNA signals for perlecan core protein and heparanase were mostly compatible with their protein signals. Ki-67-positive cells were localized mainly in the second basal cell layers with definitely higher labeling indices (approximately 31.3%, second layer). In contrast to KCOT, dentigerous cysts and radicular cysts had no perlecan, HS chains, and heparanase deposition in their linings with extremely lower Ki-67 indices (0.4–0.8%).
Conclusion:  The result suggests that the characteristic intra-lining-epithelial deposit of perlecan in KCOT, which has never been seen in other cystic jaw lesions, is a new evidence supporting the neoplastic nature of KCOT.     

Prevalence of developmental odontogenic cysts in children and adolescents with emphasis on dentigerous cyst and odontogenic keratocyst (keratocystic odontogenic tumor)

Objective. To investigate the incidence and prevalence of developmental odontogenic cysts in children and adolescents and compare the features of the two most common types, dentigerous cyst and keratocystic odontogenic tumor (KCOT). Study design. A retrospective review in a series of 369 patients with all histological diagnoses of developmental odontogenic cysts in children (≤12 years) and adolescents (13–18 years) was conducted. Results. Among these, 361 (97.8%) patients were diagnosed as dentigerous cyst (n = 281) and KCOT (n = 80), with the male-to-female ratios of dentigerous cyst and KCOT both being 2:1. The average age of the patients with KCOT was older than that of those with dentigerous cyst (14.7 years vs 11.8 years, p < 0.001). Dentigerous cyst (59.1%) was more common in children, but KCOT (78.8%) was more common in adolescents (p < 0.001). Dentigerous cyst (57.6%) predominantly located on the maxilla, but KCOT (60.3%) predominantly located on the mandible (p = 0.010). Conclusions. Adolescent patients with lesions located on the mandible would favor KCOT over dentigerous cyst. This study aids in better knowledge of the prevalence of developmental odontogenic cysts in a large pediatric population, and shows that a well-supported early diagnosis is indispensable for a more adequate treatment.     

细胞角蛋白及其mRNA在根端囊肿上皮衬里中的表达

目的本研究目的是探讨根端囊肿上皮衬里细胞角蛋白及其mRNA的表达情况.方法检测52例根端囊肿衬里上皮的细胞角蛋白(CK8,CK13和CK18)的表达,其中采用免疫组化染色法检测32例上颌根端囊肿和20例下颌根端囊肿;采用原位杂交法检测24例上颌根端囊肿和13例下颌根端囊肿CK-mRNA表达;采用逆转录聚合酶链反应(RT-PCR)法检测24例上颌囊肿.结果上颌根端囊肿中CK8,CK13,CK18阳性的鳞状上皮衬里分别是20例,29例和19例,下颌根端囊肿中表达阳性的分别为10例,20例和11例.上颌根端囊肿中[CK18( )-CK13(-)]3例,[CK18( )-CK13( )]13例,[CK18(-)-CK13( )]13例,而下颌根端囊肿中[CK18( )-CK13(-)]0例,[CK18( )-CK13( )]11例,[CK18(-)-CK13( )]9例.原位杂交显示24例上颌根端囊肿和13例下颌根端囊肿分别有9例和4例囊肿衬里中有CK18-mRNA表达.RT-PCR检测发现CK18-mRNA和CK13-mRNA在正常鼻窦粘膜和牙龈上皮(对照组)及上颌囊肿衬里都有表达.结论CK18-mRNA和CK13-mRNA在根端囊肿鳞状上皮和柱状上皮基本上都有表达.上颌根端囊肿中CK蛋白及其CK18-mRNA表达的不同,可能是囊肿上皮衬里基因型发生转变的结果.     

Lipopigment in odontogenic cysts

A study of 105 odontogenic cysts revealed the presence of pigmented cells in the cyst wall in 38% of the cases. The frequency of pigmented cells was higher in the inflammatory odontogenic cysts than in the developmental cysts. Although isolated pigmented cells were seen within the epithelial lining and cyst cavity, the larger collections were closely associated with cholesterol crystals and hemosiderin deposits; they contained light brown cytoplasmic pigment which manifested sudanophilia, acid-fastness, silver reduction capacity, PAS positivity and yellow autofluorescence in ultraviolet light. The morphology, histochemical reactions and autofluorescence suggest that the pigmented cells are macrophages containing ceroids. It has been suggested that the hemosiderin which is found in the cyst wall serves as an oxidation catalyst for the locally liberated lipids, the end result of which is the formation of the ceroid pigment.     

细胞角蛋白(CK)13在含牙囊肿衬里上皮的表达

目的 研究纤毛柱状上皮向鳞状上皮化生时细胞角蛋白13的表达，探讨其表达在上皮化生方面的意义。方法 取54例含牙囊肿和6例鼻腭管囊肿，分别采用细胞角蛋白13单克隆抗体进行免疫组织化学染色、HE染色和RT-PCR方法研究细胞角蛋白13基因的表达。结果 54例含牙囊肿中，46例为复屡鳞状上皮细胞衬里，CK13均呈阳性表达；8例混合性上皮衬里，其中的鳞状上皮细胞部分CK13也呈阳性表达；纤毛柱状上皮部分和6例鼻腭管囊肿的纤毛柱状上皮细胞均呈阴性表达。RT-PCR结果显示细胞角蛋白13基因在复屡鳞状上皮中表达最强，在混合性上皮中表达减弱，在纤毛柱状上皮中表达极弱。结论 细胞角蛋白13基因（CK13-mRNA）在纤毛柱状上皮、混和性上皮和复屡鳞状上皮三种不同上皮衬里中均有表达，但表达强度不同。呈由弱到强的变化。在鳞状上皮细胞中细胞角蛋白13呈强阳性表达；在纤毛柱状上皮细胞中细胞角蛋白13呈阴性；可是，当纤毛柱状上皮中出现鳞状上皮细胞时，可见细胞角蛋白13呈阳性表达，因而，细胞角蛋白13是纤毛柱状上皮细胞向鳞状上皮细胞化生过程中的标志性产物，但是有待进一步验证。     

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由于颌骨内的成牙组织常可作为囊肿和肿瘤的组织来源,因此颌骨是人类骨骼中最好发上皮性囊肿和肿瘤的部位。这类牙源性病损好发于年轻人,可造成颌骨及邻近组织的破坏,导致口腔颌面部外形改变,某些侵袭性病损具有较高的复发倾向,可对患者的生存质量及心理健康造成严重影响。本文着重讨论几种常见的牙源性囊肿与牙源性肿瘤的病理学诊断。     

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牙源性囊肿与牙源性肿瘤是口腔颌面部较为常见的疾病。由于临床表现的多样性,易与其他类型的颌面部囊肿或肿瘤相混淆,而且不同类型的牙源性囊肿和肿瘤其治疗方案也有所区别,所以牙源性囊肿及肿瘤的术前诊断对于其治疗方案的选择起着关键的作用,而在其诊治的过程中,影像学检查起到了非常重要的作用;不同类型的牙源性囊肿及肿瘤的影像学表现也各具特征。本文对常见的牙源性囊肿(牙源性角化囊肿等)及肿瘤(成釉细胞瘤、恶性成釉细胞瘤等)的影像学表现结合实际的影像学图片作简单的介绍,比较各种影像学检查在上述疾病诊断中所具有的优点,以期望能将CT、MRI及全景片等影像学检查手段更好的运用于上述疾病的诊治中。