Immunohistochemical demonstration of an enamel sheath protein, sheathlin, in odontogenic tumors

Enamel proteins can be useful markers for assessment of the functional differentiation of neoplastic epithelium and the nature of extracellular matrices in odontogenic tumors. In the present study, we examined immunohistochemical localization of sheathlin, a recently cloned enamel sheath protein, in various odontogenic tumors to evaluate functional differentiation of tumor cells and the nature of hyalinous or calcified matrices in odontogenic neoplasms. Distinct immunolocalization of sheathlin was observed in the immature enamel of the tooth germ at the late bell stage. Secretory ameloblasts facing the enamel matrix also showed positive staining in their cytoplasm. Definite localization of sheathlin was demonstrated in the enamel matrix in odontogenic tumors with inductive dental hard tissue formation such as ameloblastic fibroodontomas and odontomas. Immunoexpression of sheathlin was, furthermore, demonstrated in eosinophilic droplets in solid nests of adenomatoid odontogenic tumor (AOT) and ghost cells in the epithelial lining of calcifying odontogenic cyst (COC). In AOT, cells facing the eosinophilic droplets also expressed the protein in their cytoplasm. There was neither intracellular staining for sheathlin in the tumor cells nor extracellular staining in the matrix of ameloblastomas and calcifying epithelial odontogenic tumors. Dentin, dysplastic dentin-like hyaline material and cementum in the tumors examined were negative for sheathlin. These results show that immunodetection of sheathlin is a useful marker for functional differentiation of secretory ameloblasts and enamel matrix, which is often hard to differentiate from other hard tissues in odontogenic tumors. Our findings from the view point of sheathlin expression support that the tumor cells of ameloblastomas do not attain full differentiation into functional ameloblasts. It is very interesting that epithelial cells in odontogenic tumors can differentiate into functional ameloblasts without induction by odontogenic mesenchyme, as shown by immunoexpression of sheathlin in eosinophilic droplets within solid epithelial sheets in AOT and ghost cells in the epithelial lining of COC where inductive participation of mesenchymal cells was most unlikely. Received: 19 May 1999 / Accepted: 27 September 1999     

Comprehensive keratin profiling reveals different histopathogenesis of keratocystic odontogenic tumor and orthokeratinized odontogenic cyst

Keratocystic odontogenic tumor is a cystic lesion that behaves more aggressively than other jaw cysts. One of its characteristic histologic features is a parakeratinized uniform layer of lining epithelium. A jaw cyst lined with orthokeratinized epithelium is called an orthokeratinized odontogenic cyst. These keratinized jaw cysts are thought to be separate entities, although their histopathogenesis has not been fully assessed. To better understand these lesions, we performed comprehensive immunohistochemical profiling of the keratin expression of each. Orthokeratinized odontogenic cysts expressed keratin 1, keratin 2, keratin 10, and loricrin, suggesting differentiation toward normal epidermis. Keratocystic odontogenic tumors expressed keratin 4, keratin 13, keratin 17, and keratin 19, which is a unique expression pattern reminiscent of a mucosal squamous epithelium and an epithelial appendage. In neonatal rat tooth germ, cells strongly positive for keratin 17 and keratin 19 were observed, specifically in the dental lamina, implying the origin of keratocystic odontogenic tumor. GLI2, a downstream effector of hedgehog signaling, was significantly expressed in keratocystic odontogenic tumor and basal cell carcinoma, accompanied with robust expression of keratin 17, mammalian target of rapamycin, and BCL2. The expression of these GLI2- or keratin 17-related factors was not significantly observed in orthokeratinized odontogenic cysts. These findings provide evidence to support the viewpoint that keratocystic odontogenic tumor and orthokeratinized odontogenic cyst are separate entities, and furthermore suggest their characteristic histology, pathogenesis, and biological behaviors.     

CD56 expression is associated with neuroectodermal differentiation in ameloblastomas: an immunohistochemical evaluation in comparison with odontogenic cystic lesions

Ameloblastoma (AB), which is the most common odontogenic tumor, may originate from the dental lamina remnants. The expression of CD56, which is a transmembrane molecule, is associated with neuroectodermal differentiation of the embryonal cells. The aim of this study was to evaluate the expression of CD56 in AB, in comparison with other odontogenic cysts. We used formalin-fi xed, paraffi n-embedded specimens from 34 cases of AB, 10 cases of keratocystic odontogenic tumor (KCOT), and 7 cases of dentigerous cyst (DC). We immunohistochemically examined CD56, NeuroD1, and N-cadherin expression in these tumors as compared with the expression patterns of various epithelial markers. Seventy-four percent of AB showed immunopositivity for CD56, and both CD56 and N-cadherin were diffusely positive in the outer columnar cells of AB. The immunopositivities for NeuroD1 and N-cadherin were also observed in the outer cells of AB. None of the DC cases was positive for CD56, whereas half the cases of KCOT were positive. Because CD56 is expressed in the inner enamel epithelium of enamel organs, the outer columnar cells of AB are likely to be the differentiation phenotype of the inner enamel epithelium, which is associated with neuroectodermal differentiation. The aberrant NeuroD1 expression may induce CD56 expression in AB and KCOT.     

Odontogenic tumor with combined characteristics of adenomatoid odontogenic and calcifying epithelial odontogenic tumors

A very rare odontogenic epithelial tumor with the combined characteristics of an adenomatoid odontogenic tumor (AOT) and calcifying epithelial odontogenic tumor (CEOT) was found in a 27 year old female. The histopathology, immunohistochemistry of keratin, lectin-binding patterns and distribution of carbonic anhydrase were determined. The nature of the calcified bodies was also examined biophysically. The tumor consisted of cuboidal and columnar odontogenic epithelial cells in the cystic wall, and AOT and CEOT in the central cavity. Odontogenic epithelial cells forming the cyst wall in the CEOT were positive for TK- and KL1-keratins, while that detected with PKK1 antibody was absent in the tumorous epithelium. Lectin binding of tumor epithelial cells was examined with Concanavalin A (Con A), peanut agglutinin (PNA), soybean agglutinin (SBA), dolichos biflorus agglutinin (DBA), wheat germ agglutinin (WGA), ricinus communis agglutinin (RCA-I), and ulex europeus agglutinin I (UEA-I) lectins, and the tumor epithelium indicated existence of glucose, mannose, Gal, GalNAc, and GlcNAc residues. The lectin binding patterns of the calcified material showed an increased intensity by enzymatic pretreatments. With an electron probe X-ray microanalyser (EPMA), the calcified lesions gave a high peak for calcium ion and for phosphorus ion and a low one for magnesium ion, as obtained from line and surface analysis.     

Immunohistochemical localization of amelogenin in human odontogenic tumors, using a polyclonal antibody against bovine amelogenin

In the present study, we investigated the localization of amelogenin in odontogenic tumors, using an anti-amelogenin polyclonal antibody. In order to make the antibody, antisera against an amelogenin fraction obtained from the enamel matrix of unerupted bovine tooth was raised in rabbits. By Western blot analysis, a main band of 25 kDa and six minor bands (6.8, 12, 18, 20, 23, and 27 kDa) were detected under nonreducing conditions. Immunoreactivity for the amelogenin was observed in ameloblasts and in the immature enamel matrix of 4-day-old rats. In odontogenic tumors, positive reactions for amelogenin were localized in limited areas in adenomatoid odontogenic tumor, calcifying odontogenic cyst, primary intraosseous carcinoma and odontoma. The strongest immunoreactions were shown in enamel matrices in odontomas. Small mineralized foci in epithelial nests showed positive reactions, and a few reactions were observed in epithelium adjacent to the mineralized foci. In calcifying odontogenic cysts, some ghost cells in the lining epithelium were strongly stained. The results indicate that the present antibody for amelogenin is useful for the determination of odontogenic tumors, especially in those in which small mineralized foci are present in the epithelial nests.     

Immunohistochemical expression of amelogenins in odontogenic epithelial tumours and cysts

Summary Amelogenins, enamel proteins in odontogenic tumours, were detected immunohistochemically using a monoclonal antibody. They were strongly expressed in amyloid-like material, ghost cells, and the cells surrounding ghost cells of calcifying epithelial odontogenic tumours and cysts, whereas calcified bodies within the tumours and cysts showed negative staining. The expression of amelogenins was also positive in tumour cells of ameloblastoma, adenomatoid odontogenic tumour, squamous odontogenic tumour and ameloblastic fibroma. Peripheral tumour cells of the follicular ameloblastoma were positive with relatively intense staining. Undifferentiated or flattened tumour cells of adenomatoid odontogenic tumour and non-keratinized tumour cells of the squamous odontogenic tumour showed marked staining. Reduced ameloblasts in the odontoma displayed the strongest staining for amelogenins. The study suggests that biosynthesis of amelogenins may occur in the homogeneous materials of calcifying epithelial odontogenic tumours and cysts.     

Calcifying odontogenic cysts: co-expression of intermediate filament proteins, and immunohistochemical distribution of keratins, involucrin, and filaggrin

The epithelia lining the cyst of five cases of calcifying odontogenic cyst (COC) were evaluated immunohistochemically with the use of monoclonal antibodies (MoAb's) against keratin (PKK1, KL1, K4.62, K8.12) and vimentin, and polyclonal antisera agonist involucrin and filaggrin. Epithelial lining of COC was classified into 1) thin squamous-cell epithelium, 2) ameloblastoma-like, and 3) thin or 4) thick calcifying odontogenic epithelium. Foci consisting of ghost cells or calcified cells were categorized as calcifying epithelial odontogenic tumor (CEOT). Thin squamous-cell epithelium reacted with PKK1, KL1, K4.62, K8.12, and anti-vimentin MoAb's, thus demonstrating the co-expression of keratin and vimentin. Ameloblastoma-like cells showed positive staining with PKK1, KL1, and sometimes with anti-vimentin. Thick calcifying odontogenic epithelial lining showed stratification of cell layers, and the most strikingly reactive zone was the upper intermediate layer, which showed the presence of keratin, involucrin, and a small amount of filaggrin. Cells of this layer might be the most differentiated type of cells in COC. Undifferentiated odontogenic cells of COC masses were characterized by co-expression of keratin and vimentin, and by the absence of involucrin and filaggrin. All ghost cells were devoid of any immunostaining except for filaggrin, which was rarely positive, but eosinophilic or basophilic cells surrounding the ghost cells showed intense staining for all keratin proteins except vimentin.     

Cytological findings of odontogenic myxofibroma: A diagnostic dilemma

Odontogenic myxofibroma represents a rare slow‐growing benign neoplasm, which usually occurs in the second and third decades of life and rarely in children or adults over 50 years of age. Myxomas in general represent from 2.3% to 17.7% of all odontogenic tumors, and myxofibromas represent a small number of all myxomas. Limited evidence is present in literature regarding the cytological diagnosis of odontogenic myxoma/myxofibroma. We hereby report the cytomorphological features of a histologically confirmed case of odontogenic myxofibroma and the pitfalls of the cytological diagnosis. A painless jaw swelling in a young boy was aspirated. Scanty mucoid material was obtained. Cytology Smears were moderately cellular and showed a population comprising predominantly of singly scattered plump to fusiform cells with bipolar cytoplasmic processes showing mild to moderate atypia embedded within dense myxoid matrix and another population of cells arranged in clusters. Case was interpreted as low grade mesenchymal tumor. Subsequent biopsy confirmed it as odontogenic myxofibroma arising in a odontogenic keratocyst. Precise interpretation of intraosseous jaw lesions FNAC may not always be possible, but an attempt should be made to broadly classify the lesion as an inflammatory lesion, cystic lesion, giant cell lesion, fibro‐osseous lesion or as an odontogenic tumor. If dual population of odontogenic epithelium and mesenchymal cells embedded in myxoid matrix are identified in such aspirates, a possibility of myxoid odontogenic tumor may be suggested. Triple correlation of cytological, clinical and radiological findings can guide the surgeon for taking appropriate therapeutic decisions. Diagn. Cytopathol. 2016;44:329–333. © 2016 Wiley Periodicals, Inc.     

Calcifying odontogenic cyst immunohistochemical detection of keratin and involucrin in cyst wall

Summary Calcifying odontogenic cysts (COC) were immunohistochemically described using different keratin proteins and involucrin as well as histopathology. The cystic lining epithelium was composed of calcifying, keratinizing, squamous, and columnar epithelial cells, and included calcified masses of irregular shape and various size as well as ghost cells. Calcifying epithelium gave negative or only trace staining for keratins detected with low molecular keratin (PKK1), but were regularly positive with high molecular keratin (KL1) and polyclonal antibody for keratin (TK). They were occasionally positive for involucrin. The cells located in the periphery of the calcified masses had a particular abundance of high molecular weight and total keratins (KL1 and TK). Calcified bodies and ghost cells were devoid of any immunoreactivity. Squamous epithelium was relatively similar to that of normal squamous cell epithelium in the oral mucosa. It were most commonly found in columnar cystic epithelial cells which displayed intense staining with all immunoreagents. It is postulated that such epithelial cells may have a strong potentiality to transform into ghost cells or to undergo metaplasia. They may develop altered synthesis of homogenous acellular materials and finally become transformed into calcifying epithelium containing dystrophic calcified masses.     

Malignant epithelial odontogenic tumors

Malignant epithelial odontogenic tumors are very rare. They may arise from the epithelial components of the odontogenic apparatus. The rests of Malassez, the reduced enamel epithelium surrounding the crown of an impacted tooth, the rests of Serres in the gingiva, and the linings of odontogenic cysts represent the precursor cells for malignant transformation. Because metastatic carcinoma is the most common malignancy of the jaws, the diagnosis of a primary intraosseous carcinoma must always be made to the exclusion of metastatic disease. Odontogenic carcinomas include malignant (metastasizing) ameloblastoma, ameloblastic carcinoma, primary intraosseous squamous cell carcinoma, clear cell odontogenic carcinoma, and malignant epithelial ghost cell tumor. There are specific histopathologic features that support the diagnosis of a primary carcinoma of odontogenic epithelium which are presented in this article. Immunohistochemical (IHC) staining is important for distinguishing clear cell odontogenic carcinoma from metastatic renal cell tumors, yet IHC stains are not particularly helpful for other lesions in this group-all of which exhibit low molecular weight cytokeratin positivity. Aggressive growth and nodal and distant metastases occur with all of these entities.     

WNT5A Expression in Ameloblastoma and Its Roles in Regulating Enamel Epithelium Tumorigenic Behaviors

Odontogenic tumors originate from the remains of migrating enamel epithelium after the completion of normal tooth genesis. These enamel epithelium remnants exhibit the ability to recapitulate the events that occur during tooth formation. Several lines of evidence suggest that aberrance in the signaling pathways similar to the ones that are used during tooth development, including the WNT pathway, might be the cause of odontogenic tumorigenesis and maintenance. In this study we demonstrated that WNT5A expression was intense in both the epithelial component of ameloblastomas, the most common epithelial odontogenic tumor, and in this tumor''s likely precursor cell, the enamel epithelium located at the cervical loop of normal developing human tooth buds. Additionally, when WNT5A was overexpressed in enamel epithelium cells (LS-8), the clones expressing high levels of WNT5A (S) exhibited characteristics of tumorigenic cells, including growth factor independence, loss of anchorage dependence, loss of contact inhibition, and tumor formation in immunocompromised mice. Moreover, overexpression of WNT5A drastically increased LS-8 cell migration and actin reorganization when compared with controls. Suppression of endogenous WNT5A in LS-8 cells (AS) greatly impaired their migration and AS cells failed to form significant actin reorganization and membrane protrusion was rarely seen. Taken together, our data indicate that WNT5A signaling is important in modulating tumorigenic behaviors of enamel epithelium cells in ameloblastomas.Odontogenic tumors comprise a group of lesions in the oral and maxillofacial region, ranging from benign to malignant neoplastic tissue. Similar to normal odontogenesis, odontogenic tumors exhibit characteristics of epithelium-mesenchyme interactions that occur during tooth genesis. After the formation of the tooth crown, enamel epithelium cells at the cervical loop directionally proliferate to the root area. After tooth formation is completed, these enamel epithelium cells are left in the periodontal ligament space and are believed to give rise to several epithelial odontogenic tumors.^1,2 According to the World Health Organization in 2005, odontogenic tumors are classified in relation to their tissues of origin into epithelial, epithelial-ectomesenchymal, and ectomesenchymal neoplasms.³Ameloblastoma, a usually benign but locally invasive tumor, is the most common odontogenic tumor derived from odontogenic epithelium. It is slow growing but has persistent growth that produces marked deformity of the face. The term “ameloblastoma” is derived from the histology of the tumor that resembles the developing enamel organ of the tooth germ.^4,5 Ameloblastoma has a high recurrence rate (50 to 90%); therefore, wide surgical resection is the preferred treatment. The molecular determinants driving initiation and maintenance of ameloblastoma remain unclear. Evidence suggests that alteration in signaling pathways that are important for normal tooth development such as tumor necrosis factor, fibroblast growth factor, Sonic Hedgehog, and wingless-type (WNT) pathways could contribute to the etiology of ameloblastoma.^6–9WNT5A (wingless-type MMTV integration site family, member 5A) belongs to the WNT family that controls several processes during embryogenesis including cell fate specification, tissue patterning, cell proliferation, cell differentiation, and cell migration.¹⁰ While WNT5A also is implicated to play an important role in a variety of cancers, the function of WNT5A in tumorigenesis is obscure and contradictory.¹¹ Evidence suggests that WNT5A possesses oncogenic properties and that WNT5A enhances the aggressive and malignant behaviors of cells in malignant melanoma,¹² gastric cancer, lung cancer,¹³ and prostate cancer.^14,15 On the other hand, WNT5A has been considered a tumor suppressor in neuroblastoma, acute myeloid leukemia, and primary dukes B colon cancer.^16–18 In the case of odontogenic tumors, WNT5A expression in ameloblastoma has been reported,¹⁹ but its biological consequence has not been explored.In the present study, we demonstrate strong WNT5A expression in the epithelial compartment of human ameloblastomas and in the enamel epithelium cells at the cervical loop during normal human tooth development. Furthermore, when overexpressed in enamel epithelium cells, LS-8, WNT5A promotes cell survival, instilling a loss of contact inhibition, loss of anchorage dependence, and increased tumor formation rate in nude mice. Overexpression of WNT5A also enhances cell migration, increases actin reorganization and filopodia/lamellipodia formation in LS-8 cells. Our results demonstrate that WNT5A overexpression has multiple effects on enamel epithelium cell behaviors that are all important characteristics of tumorigenic cells.     

造釉细胞瘤中抗凋零基因bc1－2表达产物的分布及意义

抗凋零基因ｂｃ１－２的表达产物可抑制细胞调零过程，从而导致肿瘤发生。我们利用免疫组化方法观察了４０例造釉细胞瘤中ｂｃ１－２基因产物的表达与分布。ｂｃ１－２基因产物主要位于正常牙胚的造釉上皮、缩余釉上皮和造牙本质细胞中，正常口腔粘膜上皮和牙源性囊肿上皮的基底层细胞可见ｂｃ１－２基因产物阳性。４０例造釉细胞瘤，ｂｃ１－２阳性病例达９０％。本文结果提示，ｂｃ１－２在牙源性上皮中的表达与细胞的分化程度有关，ｂｃ１－２的过量表达可能参与了造釉细胞瘤的形态发生过程。     

Epithelial odontogenic tumours in domestic animals

Epithelial odontogenic tumours are uncommon, poorly understood and often difficult to diagnose, oral neoplasms. Dental organ pre-ameloblasts and basal lamina induce development of mesenchymal cells into odontoblasts, which produce dentin and induce pre-ameloblasts to mature into secretory ameloblasts. These reciprocal sequential inductive interactions between dental epithelium and mesenchyme form the basis for classifying epithelial odontogenic tumours. There are three tumours classified as non-inductive: ameloblastoma characterized by cords and islands of stellate reticulum with peripheral palisades of polarized columnar cells, adenomatoid ameloblastoma which has acini, rosettes and ducts of polarized columnar cells and stellate reticulum and calcifying epithelial odontogenic tumour which contains foci of Congo-red-positive material surrounded by pleomorphic polygonal epithelial cells. There are five tumours in which induction of mesenchymal tissue is evident: ameloblastic fibroma with characteristics of ameloblastoma plus proliferation of closely associated pulp-like mesenchyme; dentinoma consisting of masses of dentin, often with minimal cellular component; ameloblastic odontoma which contains palisaded epithelium and stellate reticulum as in ameloblastoma, as well as foci of dentin and/or enamel; complex odontoma which is a disorderly array of dentin, enamel, ameloblastic epithelium and odontoblasts; and compound odontoma containing denticles with well-organized tooth morphology. This paper reviews the embryogenesis of teeth and describes six types of epithelial odontogenic tumours in 13 animals. The literature concerning these tumours in nearly 250 animals is reviewed. The most commonly reported tumour is ameloblastoma and the species in which all types are most commonly reported is the dog.     

Benigne odontogene ektomesenchymale Tumoren

The group of odontogenic ectomesenchymal tumors consists of odontogenic fibroma (epithelium-rich and epithelium-poor types), odontogenic myxoma, and cementoblastoma. Whereas odontogenic fibromas and cementoblastomas are very rare lesions, odontogenic myxoma is the fourth common odontogenic tumor, preceded only by keratocystic odontogenic tumor, the odontomas, and ameloblastoma. The diagnosis of cementoblastoma rests on its connection to the root of a tooth. The differentiation of odontogenic fibroma and myxoma from other lesions, especially from normal structures such as dental follicles and papillae, may be challenging if the X-ray appearance (localized osteolysis containing a tooth) is not appreciated and subtle histological clues (remainders of inner enamel epithelium at the surface of the lesion, dentin fragments) are not properly recognized. While odontogenic fibromas have almost no tendency for recurrence and are treated by enucleation or local excision, cementoblastomas and especially odontogenic myxomas have a high percentage of recurrence if intralesional procedures are applied. Hence, complete resection with free margins is recommended--at least for larger odontogenic myxomas and, especially, lesions in the maxilla--to prevent further extension to the orbita or base of the skull.     

Primary Osteosarcoma of the Ovary

A case of primary osteosarcoma arising in the left ovary of a 75 year-old female is described. The chief complaint was a sensation of lower abdominal mass. An abdominal plain film showed a large calcified mass in pelvic region, and a preoperative diagnosis of "ovarian fibroma" was made. The excised tumor was divided into 4 pieces, resembling an oyster shell. Microscopically, the tumor fragments were composed of compact bone or woven bone with surrounding atypical osteoblasts and osteoclasts. The tumor was partly composed of numerous spindle cells with malignant osteoid or atypical chondroid formation, and diagnosed as "osteosarcoma". The cystic part of the lesion was lined with a single layer of columnar cells, but the tumor contained no other germ elements or stem cells, or malignant epithelium. Therefore, it is doubtful that this tumor originated from teratoma or malignant mixed mesodermal tumor, and we conclude that this ovarian osteosarcoma arose through a neoplastic change in ovarian stromal cells. The patient died 4 months after surgery due to intra-abdominal and intrathoracic dissemination of the tumor.     

Primary osteosarcoma of the ovary. A case report.

A case of primary osteosarcoma arising in the left ovary of a 75-year-old female is described. The chief complaint was a sensation of lower abdominal mass. An abdominal plain film showed a large calcified mass in pelvic region, and a preoperative diagnosis of "ovarian fibroma" was made. The excised tumor was divided into 4 pieces, resembling an oyster shell. Microscopically, the tumor fragments were composed of compact bone or woven bone with surrounding atypical osteoblasts and osteoclasts. The tumor was partly composed of numerous spindle cells with malignant osteoid or atypical chondroid formation, and diagnosed as "osteosarcoma". The cystic part of the lesion was lined with a single layer of columnar cells, but the tumor contained no other germ elements or stem cells, or malignant epithelium. Therefore, it is doubtful that this tumor originated from teratoma or malignant mixed mesodermal tumor, and we conclude that this ovarian osteosarcoma arose through a neoplastic change in ovarian stromal cells. The patient died 4 months after surgery due to intra-abdominal and intrathoracic dissemination of the tumor.     

Keratoameloblastoma with unique histological architecture: an undescribed variation of ameloblastoma

Keratoameloblastoma is an extremely rare variant of ameloblastoma, and a review of the English language literature yields only several documented cases of ketatoameloblastoma. This paper reports a keratoameloblastoma showing unique histological architecture. The patient was a 76-year-old Japanese man with a multilocular radiolucent lesion of the mandible extending from the left canine to the second molar area. Microscopically, the lesion was characterized by multicystic spaces lined by papillary projections of proliferating odontogenic epithelium with extensive surface parakeratinization in a lamellar accumulation of keratin. In addition, "hair-like" extensions of keratin were frequently found. There was no ghost cell type keratinization. Histological features of the odontogenic epithelium were similar to those of conventinal ameloblastoma. An additional prominent feature of the present ameloblastoma was formation of hard tissue in continuation, in part, of the accumulated keratin in the fibrous tissue. These hard tissues showed a woven bone- or cellular cementum-like appearance and were not in contact with odontogenic epithelium. The present case was finally diagnosed as "keratoa meloblastoma," although such a type of keratoameloblastoma has not been documented previously in the spectrum of ameloblastoma.     

牙源性钙化囊性瘤临床病理研究

目的探讨牙源性钙化囊性瘤(calcifying cystic odontogenic tumor,CCOT)的临床病理分型对治疗预后的影响。方法对39例CCOT的临床表现、X线影象、病理特征及治疗随访资料等进行回顾性分析。结果 39例中男性26例,女性13例,平均年龄29.6岁;病变位于下颌骨21例,上颌骨18例;临床多以颜面部肿胀就诊。X线主要表现为颌骨内界限清楚的放射透光区,单房或多房,其中伴有钙化斑点或团块。镜下均可见到特征性的影细胞,可分为4种类型:单纯囊肿型(17例)、CCOT伴牙瘤型(12例)、CCOT伴成釉细胞瘤增生型(7例)、CCOT伴其他良性牙源性肿瘤型(3例:伴成釉细胞纤维瘤2例,伴成釉细胞纤维牙瘤1例)。治疗均采用囊肿摘除术或刮治术,获得随访33例,复发6例,其中3例复发者均为CCOT伴成釉细胞瘤增生型且有囊壁内浸润(1例复发为牙源性影细胞瘤,1例20年后复发恶变为牙源性影细胞癌)。结论 CCOT伴成釉细胞瘤增生且有囊壁内浸润型行单纯囊肿摘除术或刮治术容易复发,可形成牙源性影细胞瘤或恶变成牙源性影细胞癌,此型肿瘤的手术范围应适当扩大并进行长期随访。