Adenomatoid odontogenic tumor: ultrastructural demonstration of two cell types and amyloid

A comparative study of syndecan-1 expression in different odontogenic tumors

BACKGROUND

Expression of various cellular/molecular factors change during the course of tumor formation from odontogenic tissues of the tooth germ. Evaluation of these factors can help provide a better perception of the tumorigenesis and biologic behavior of odontogenic tumors (OTs). Syndecan-1 is a heparan sulfate proteoglycan which has not been extensively investigated in these lesions. The objective of the present study was to assess the immunohistochemical expression of CD138 in adenomatoid odontogenic tumor (AOT), ameloblastic fibroma (AF) and odontogenic myxoma (OM) and to compare it with ameloblastoma and keratocystic odontogenic tumor (KCOT).

METHOD

A total of 58 OTs consisting of 7 AOTs, 5 OMs, 7 AFs, 29 KCOTs and 10 ameloblastomas were immunohistochemically stained with monoclonal antibody against syndecan-1 and the percentage and intensity of the immunostained cells was assessed. Kruskal-Wallis test followed by Bonferroni analysis was used for comparisons (P < 0.05).

RESULTS

Syndecan-1 was expressed in all samples except for OMs. Both percentage and intensity of syndecan-1 expression were statistically different among the studied OTs (P < 0.001). Pairwise comparisons showed significant difference only between OMs and each of the other tumors.

CONCLUSION

Syndecan-1 may be involved in the pathogenesis of AOT, AF, KCOT and ameloblastoma. However, considering the different behaviors of these tumors along with their similar expression of syndecan-1, it seems that its effect on clinical aggressiveness is limited. The significance of negative immunoexpression of this protein in OM requires further investigation.

Cytokeratin 14 and cytokeratin 18 expressions in reduced enamel epithelium and dentigerous cyst: Possible role in oncofetal transformation and histogenesis- of follicular type of adenomatoid odontogenic tumor

Introduction:

Odontogenic cysts and tumors arise from the structures and remnants associated with tooth development. Cysts and tumors derived from the odontogenic tissues constitute an unusually diverse group of lesions. This diversity reflects the complex development of the dental structures, since all these lesions originate through some alteration from the normal pattern of odontogenesis. Cytokeratin (CK) 14 is the typical intermediary filament of odontogenic epithelium, CK 18 is the major components of the intermediate filaments of simple or single layered epithelial tissue; it is not expressed in stratified squamous epithelium. The present study was undertaken to understand the expression pattern of these cytokeratins in dentigerous cyst, dental follicular tissue, adenomatoid odontogenic tumor (AOT) and unicystic ameloblastoma.

Materials and Methods:

The present study consists of 60 specimens consisting of 20 samples of Dentigerous cyst, 20 samples of Reduced enamel epithelium/dental follicles, 10 samples of Follicular type of AOT, 10 samples of unicystic ameloblastoma. The sections of these specimens were stained for CK 14 and CK 18. The number of cells positive for CK 14 and CK 18 was counted per 100 cells. The cells were counted in four randomly selected high-power fields and the mean was calculated. Scoring of cytokeratin 14 expressions was done using Remmele score.

Results:

The highest expression of cytokeratin 14 was noted in AOT, least was seen in dental follicle/Reduced enamel epithelium (REE). CK18 was negative in all the cases included in the present study.

Conclusion:

In the present study, the expression of CK14 was noted in AOT, Dentigerous cyst (DC), Unicystic Ameloblastoma (UCA) and Dental follicle/REE. The expressions between these lesions were compared. These expression pattern may provide an insight to the histogenesis of AOT.

Critical evaluation of the radiological and clinical features of adenomatoid odontogenic tumour

OBJECTIVES

The aim of this study was to evaluate the radiological and clinical features of adenomatoid odontogenic tumours (AOTs).

METHODS

A total of 272 cases (267 from the English-language literature and 5 new cases) were analysed with special emphasis on their radiological features.

RESULTS

The patients' ages at time of diagnosis ranged from 3 years to 82 years (mean 18.4 years). The maxilla-to-mandible ratio was 1.7:1. Mandibular lesions were significantly more frequent among patients older than 16 years (p = 0.032). Expansion of the cortex was significantly more prominent among patients older than 16 years (p = 0.045). There was a positive correlation between the size of the lesion and the age of the patient at the time of diagnosis (p = 0.016). The size was also associated with increased root resorption (p < 0.001), ill-defined borders (p < 0.001), expansion (p < 0.001) and perforation of the cortex (p < 0.001). Small opacities were present in 77% of lesions and were associated with expansion of the cortex (p = 0.043). The significant radiological features in patients aged 30 years and above were root resorption (p = 0.013) and lesions crossing the midline (p = 0.019).

CONCLUSIONS

The size of an AOT is influenced by the patient's age. It is also associated with root resorption, ill-defined borders, expansion and perforation of the cortex, but it cannot be ruled out that those changes reflect a longer duration of the lesion.

Adenomatoid odontogenic tumour of the maxillary sinus

A typical adenomatoid odontogenic tumour removed from the left maxillary sinus of a fifteen years old male is reported.

Adenomatoid odontogenic tumor presenting as periapical disease

Adenomatoid odontogenic tumor commonly occurs in association with the crowns of unerupted teeth. An extrafollicular variant, radiographically in relationship to root apices, has been reported. However, clear association with the root apices at surgery has not been demonstrated. We report a case of adenomatoid odontogenic tumor in the anterior mandible in a 21-year-old woman that presented radiographically at the root apices and at surgery as a radicular cyst. We believe this represents the first reported case of adenomatoid odontogenic tumor presenting as periapical disease both clinically and radiographically. The diagnosis of adenomatoid odontogenic tumor should be considered when the clinician is presented with a corticated radiolucency in the anterior jaw, especially in teens and young adults.

The adenomatoid odontogenic tumour: ultrastructure of tumour cells and non-calcified amorphous masses

The ultrastructure of tumour cells and tumour droplets (TD, non-calcified amorphous masses) was studied in three cases of AOT using freshly prepared tissue. The fine structure of the epithelial tumour cells (cell type I-III) corresponded to that of earlier descriptions. The extracellular location of TD was clearly demonstrated. TD were of varying, sometimes bizarre, configuration. Some TD showed a homogeneous matrix; however, in addition most revealed electron-dense plaques. At high magnification, homogeneous types of TD showed only tubular elements; all others revealed granulo-tubular structures. The tubular elements were arranged concentrically. The nature of the TD is discussed and compared to former interpretations. From the present ultrastructural findings, it appears that the TD most probably represent some form of enamel matrix and as such may be considered a type of pre-enamel. Further studies are needed to elucidate the complex structure of the TD-material so characteristic of the AOT.

Odontogenic adenomatoid tumors associated with orthodontic treatment

Because of a predilection for occurrence in the anterior jaw in association with an unerupted tooth, the odontogenic adenomatoid tumor (OAT) will sometimes be discovered in the context of an orthodontic procedure to promote and guide eruption of the tooth. Two cases illustrate this situation. Some other lesions that might have a clinical presentation similar to the OAT are named.

Adenomatoid odontogenic tumour with features of calcifying epithelial odontogenic tumour. (The so-called combined epithelial odontogenic tumour.) Clinico-pathological report of 12 cases

The combination of two odontogenic tumours is a rarely reported finding. To date only 10 cases of adenomatoid odontogenic tumour (AOT) combined with areas of calcifying epithelial odontogenic tumour (CEOT) have been published. This article describes the clinical, radiographical and microscopic findings of 12 cases of AOT, in which CEOT-like areas of variable sizes were found. These results suggest that such areas may be considered as a normal feature within the histomorphological spectrum of AOT.

The nature of the eosinophilic and laminated masses in the adenomatoid odontogenic tumor: a histochemical and ultrastructural study

The eosinophilic and laminated masses in AOT were investigated with the light and electron microscope in two cases. The results showed that the eosinophilic amorphous masses were heterogenous and consisted mainly of three types of fibrils. These were: thin collagen, electron dense fibrils probably resulting from degradation of collagen and masses of amyloid filaments with or without collagen fibers in normal and degraded forms. In addition some of the eosinophilic deposits resulted from changes surrounding blood vessels which led to deposition of either collagen or fine filaments arranged into layers around these vessels. In all these areas there was a peripheral layer of fine filaments perpendicular to the epithelial basal lamina, similar to that found in early dentin formation. This layer may be responsible for the reticulin staining found in this tumor. On the other hand the great majority of the laminated masses represented calcified amyloid with or without areas of calcified degraded collagen which were indistinguishable from amyloid. The results suggest that the various fibrils forming the eosinophilic masses in AOT are probably related and may be the result of changes in blood vessels. They also revealed that calcification involves mainly amyloid.

The combined epithelial odontogenic tumour in Malaysians

The combined epithelial odontogenic tumour represents a hybrid lesion comprising primarily areas of adenomatoid odontogenic tumour intermixed with foci of calcifying epithelial odontogenic tumour. Five such cases retrieved from the files of the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, and four others from the existing literature were analysed. A mean age of 18.8 years, a female preponderance (66.7%) with a male to female ratio of 1:2 and predilection for the mandible (55.6%) were observed. All cases were treated by conservative surgery and the lack of recurrence confirmed the innocuous nature of this lesion.

Adenomatoid odontogenic tumor: biologic profile based on 499 cases

Topographically, the AOT occurs in peripheral and central variants, the latter further in follicular (with embedded tooth) and extrafollicular (no embedded tooth) types. The AOT is slow growing with few or no symptoms. Tumor growth may cause displacement of teeth rather than root resorption. The follicular AOT mimics a follicular cyst, the extrafollicular a residual or "globulo-maxillary" cyst and the peripheral a gingival fibroma. All variants of AOT show identical histologic features. The central variants account for 97.2%, 73.0% of which are follicular. The follicular variant (M:F ratio 1 to 1.9) is three times as frequent as the extrafollicular. The follicular variant is diagnosed earlier in life (mean age 17 yr) than the extrafollicular (mean age 24 yr). 53.1% of all variants occur within the teens (13-19 yr). Follicular AOT is associated with one embedded tooth in 93.2%. Maxillary permanent canines account for 41.7% and all four canines for 60.1% of AOT-associated embedded teeth. Ranking four among the odontogenic tumors the AOT is not a particularly rare tumor. Conservative surgical excision is the treatment of choice. Documented recurrences have not been reported.

Adenomatoid odontogenic tumour: co-expression of keratin and vimentin

Immunohistochemical observations of intermediate sized proteins in five cases of adenomatoid odontogenic tumour (AOT) are described. The immunohistochemical detections of keratins were made with polyclonal antiserum (TK, 41-65 kDa) and three monoclonal keratin antibodies (KL1: 55-57 kDa; PKK1: 40, 45, and 52.5 kDa and nos. 19, 18, 8; K8.12: nos. 16, 13) and vimentin and desmin monoclonal antibodies. Histologically, the tumour epithelia could be divided into two types: type A cells were a spindle or columnar shape and formed solid, ductal, tubular or whorled structures. Type B cells were small and compact cells at the periphery of the A cell-containing focus. Immunohistochemically, the type A cells showed very slight reaction with all antibodies to keratins, whereas the type B cells indicated slight-to-moderate expression of keratin and vimentin, and showed coexpression. Both types of cell showed a negative reaction for desmin. Only one case was associated with cystic lesions, and the cyst-lining was composed of thin squamous epithelium. Keratin expression in this epithelium was strong. In the histogenesis of AOT it was postulated that the tumour cells may have originated from undifferentiated odontogenic epithelium or stratum intermedium cells.

Adenomatoid odontogenic tumor mimicking a globulo-maxillary cyst

A case of an adenomatoid odontogenic tumor (AOT) simulating a globulo-maxillary cyst is described. Clinical, radiographic and microscopic findings as well as the differential diagnosis are discussed. The present case brings the number of AOT cases without any relationship to an impacted tooth to 23; the number of cases resembling a globulo-maxillary cyst to 6.

Adenomatoid odontogenic tumor associated with calcifying epithelial odontogenic tumor

A case of odontogenic tumor which contained areas diagnostic for both adenomatoid odontogenic tumor and calcifying epithelial odontogenic tumor arising in the upper left anterior region in a 17-year-old Japanese female is reported. The histopathological observation suggested that the lesion represented primarily adenomatoid odontogenic tumor in which multiple foci of calcifying epithelial odontogenic tumor had developed.

Adenomatoid odontogenic tumor in a black African population: report of thirteen cases

The records of the Cancer Registry of University College Hospital in Ibadan, Nigeria, were reviewed for the incidence of adenomatoid odontogenic tumor from 1961-1982. Thirteen cases of the tumor were found. Clinical, histologic, and radiologic features of the 13 cases are reported. Many features were similar to previous reports of this tumor, but an increased ratio of males to females and preference for the mandible was observed. It is suggested that these factors may be peculiar to Nigerians. A few cases showed an unusual posterior location of tumor.

Histoenzymological and ultrastructural study of a bifocal calcifying epithelial odontogenic tumor. Characteristics of epithelial cells and histogenesis of amyloid-like material

A calcifying epithelial odontogenic tumor, simultaneously located in the two jaws (maxilla and mandible) was examined by histochemical and electron microscopic methods. Squamous tumor cells without secretory polarity were different from those of common ameloblastoma. High activities of alkaline phosphatase and ATPases were demonstrated by light and electron microscopy on the cytoplasmic membrane, findings similar to those in the stratum intermedium cells of the normal dental germ from which these tumor cells seem to arise. The tumor cells, like preameloblasts of the dental germ, also produce a granulo-filamentous material in intracytoplasmic vesicles and discharge it into the stroma. This "pseudo-amyloid" substance represents an abnormal protein of the enamel matrix and calcification, mainly occurring in that substance, might be an attempt at mineralization.

Adenomatoid odontogenic tumor: clinicopathologic and ultrastructural concepts

Two cases of adenomatoid odontogenic tumor have been presented, along with a review of the literature. One tumor had a rather typical presentation, occurring in a 12-year-old in association with an impacted canine tooth. Subsequent electron microscopic evaluation of this case provided corroboration of other recently published findings. In this case there was a striking accumulation of what could have been secretory granules at the pole of the cell nearest a "duct-like" space. This cell had ultrastructural characteristics in common with a preameloblast. The second case occurred in a more unusual situation, the patient being a 32-year-old man, with the AOT developing in the mandible between the roots of the canine and first premolar. Both patients were treated successfully by simple enucleation of the lesion.

Combined epithelial odontogenic tumor: adenomatoid odontogenic tumor and calcifying epithelial odontogenic tumor

1. Two cases of a combined epithelial odontogenic tumor which had areas of AOT and CEOT were presented. 2. A review of the studies on histogenesis of the AOT revealed that the tumor probably consists of preameloblasts, stratum intermedium, and stellate reticulum. 3. A review of the studies on histogenesis of the CEOT revealed that the probable origin was in cells of stratum intermedium. 4. It is suggested that the present cases support the aforementioned theories of histogenesis and represent AOT's which contain foci of CEOT. 5. The suggested treatment is simple surgical excision.

The eosinophilic and amyloid-like materials in adenomatoid odontogenic tumor

This paper is concerned with the relationship between eosinophilic material (EM) and amyloid-like material and adenomatoid odontogenic tumors. In duct-like structures between opposing rows of tall columnar cells, EM did not stain for amyloid. Under electron microscopy, EM was composed of fibrillar and granular materials, and the fibrillar material was not amyloid. Two different kinds of EM were found in solid cell masses. Lesions from cases 2, 3, 4 and part of case 1 contained small droplet-shaped EM and these EM did not stain for amyloid. Case 1 also contained EM that stained positively for amyloid. The structure of amyloid positive EM resembled developing enamel of human tooth germs. This material was tubular and finely granular. The tubular material resembled enamel matrix fibers rather then amyloid and the fine granular material was stippled. The cells surrounding EM appeared similar to ameloblasts between secretory and maturation stages.

Adenomatoid odontogenic tumor: light and electron microscopic study

A case of adenomatoid odontogenic tumor involving the right upper cuspid region of a 17-year-old girl is described. In light microscopy, liminal structures and rosette-like structures were found in the parenchyma of the tumor. Electron microscopic observations revealed that the rosette-like structures were less organized than the luminal structures; the luminal structures are supposed to be associated with secretory activities including the formation of calcified material which show the apatite pattern by electron diffraction. The origin and differentiation of cells constituting the tumor are discussed.

The ultrastructure of the adenomatoid odontogenic tumor

An adenomatoid odontogenic tumor (AOT) which occurred in the maxilla of an 8-year-old boy was studied by the light and electron microscopy. The tumor was found to contain cells resembling preameloblasts, the stratum intermedium, and the stellate reticulum, suggesting its origin from the enamel organ, in agreement with previous reports. Characteristic ductlike structures are thought to be formed as a result of secretory activity of the tumor cells, rather than degeneration. Duct-lining cells ultrastructurally similar to preameloblasts were found to contain electron-dense granules. These granules are believed to play a role in secretion by tumor cells, a concept not previously considered. The results of previous ultrastructural studies of the AOT are reviewed and summarized.