A clinical and electron microscopic study of a calcifying epithelial odontogenic tumour

Cystic variant of calcifying epithelial odontogenic tumor

The calcifying epithelial odontogenic tumor is a rare benign odontogenic neoplasm of the jaw. Clinically, calcifying epithelial odontogenic tumor manifests as an intraosseous lesion (central type) in the majority of cases (95%). Extraosseous or peripheral lesions account for less than 5% of cases. Calcifying epithelial odontogenic tumor can be associated with an impacted tooth and give a radiographic simulation of dentigerous cyst. Most calcifying epithelial odontogenic tumors are solid in nature, histopathologically, and might have few cyst-like spaces within them. However, a true cystic calcifying epithelial odontogenic tumor is a rare possibility. We describe a case of a true cystic variant of calcifying epithelial odontogenic tumor in a 30-year-old male, which to our knowledge, is only the second reported case.

Oral Masses in Two Cats

Incisional biopsies from the oral cavity of 2 adult cats were submitted for histological investigation. Cat No. 1 showed a solitary well-circumscribed neoplasm in the left mandible. Cat No. 2 demonstrated a diffusely infiltrating neoplasm in the left maxilla. Both tumors consisted of medium-size epithelial cells embedded in a fibrovascular stroma. The mitotic index was 0 to 1 mitosis per high-power field. The epithelial cells showed an irregular arrangement forming nests or streams in cat No. 1, whereas a palisading growth was noted in cat No. 2. Both tumors, especially that of cat No. 1, showed multifocal accumulations of amyloid as confirmed by Congo red staining and a distinct green birefringence under polarized light, which lacked cytokeratin immunoreactivity as well as and AL and AA amyloid immunoreactivity. In addition, the amyloid in cat No. 2 was positive for the odontogenic ameloblast-associated protein, formerly termed APin. In sum, both cats suffered from an amyloid-producing odontogenic tumor, but their tumors varied with respect to morphology and type of amyloid produced.

Cystic variant of calcifying epithelial odontogenic tumor

Calcifying epithelial odontogenic tumor (CEOT) is a benign, locally aggressive odontogenic neoplasm characterized by sheets and nests of epithelial cells with deeply eosinophilic or occasionally clear cytoplasm, calcifications, and eosinophilic amorphous material that stains positive for amyloid. Although many cases of CEOT are associated with impacted teeth and occasionally appear radiographically as dentigerous cysts, a true cystic variant has not been previously reported. We report a 15-year-old white male with a large cystic maxillary lesion that filled most of the left maxillary sinus. It deformed the medial wall, the inferior orbital floor, and caused narrowing of the left inferior meatus. Histologically, the cystic lining showed characteristics of CEOT. An intraluminal component that featured histologic characteristics of CEOT was identified during surgery. The lesion was enucleated and the postsurgical course of the patient was uneventful. Because follow-up has been for less than 1 year, a meaningful long-term prognosis cannot be determined at present. However, the patient has not reported any symptoms or signs of recurrence during the follow-up period.

The amyloid deposit in calcifying epithelial odontogenic tumor is immunoreactive for cytokeratins

Calcifying epithelial odontogenic tumor, also known as Pindborg tumor, is a rare benign tumor with locally aggressive behavior. It is characterized by squamous epithelial cells, calcifications, and eosinophilic deposits that have been identified as amyloid. We report a case of calcifying epithelial odontogenic tumor and investigate the nature of the amyloid, using histologic, immunohistochemical, and ultrastructural studies. The amyloid was immunohistochemically negative for basement membrane components and positive for all cytokeratin stains performed (cocktail of cytokeratins 1, 5, 6, 8, 13, and 16, and cytokeratins AE1 and AE3). The amyloid stained focally in a glandular-like pattern, reminiscent of the epithelial glandlike structures of the tumor. We conclude that the amyloid is derived from filamentous degeneration of keratin filaments that originate from the tumor squamous epithelium. The keratin degeneration is part of a developmental or aging process that the tumor undergoes.

Calcifying epithelial odontogenic tumours in small domesticated carnivores: histological, immunohistochemical and electron microscopical studies

Histological, immunohistochemical and electron microscopical studies revealed one feline and four canine calcifying epithelial odontogenic tumours in 115 oral tumours over a 10-year period. The tumours consisted of islands and sheets of odontogenic epithelium of varying size within a stroma of fibrous connective tissues. The tumour cells were pleomorphic with variable amounts of eosinophilic cytoplasm and large hyperchromatic, polymorphic nuclei with prominent nucleoli. Clusters of keratinized tumour cells ("shadow cells") were frequently seen within the islands and sheets. The multiple spherules of homogeneous eosinophilic material stained positively with Congo red and Dylon stains and produced an apple green birefringence under polarization microscopy, indicative of amyloid. Mineralized foci were scattered throughout the tumour masses and in the homogeneous spherules. Immunohistochemically, the tumour cells reacted with anti-human keratin antibody, but not with anti-human vimentin or anti-chicken desmin antibodies. The homogeneous spherules did not react with anti-human keratin, anti-human vimentin, anti-chicken desmin, anti-amyloid A, anti-laminin or anti-human collagen (type I, III, IV) antibodies. Ultrastructurally, the cytoplasm of tumour cells was abundant and contained a large number of electron-dense bundles of tonofilaments. The homogeneous spherules consisted of fine filaments measuring about 10-12 nm in diameter.

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.

A variant of calcifying epithelial odontogenic tumor with Langerhans cells

A variant of calcifying epithelial odontogenic tumor (CEOT) with Langerhans cells is reported. Compared to a typical CEOT, the tumor islands of this case were thin and composed of a small number of polyhedral epithelial cells. Almost no calcification of homogeneous eosinophilic materials was observed. In addition, clear cells which structurally corresponded to Langerhans cell were intermingled in the epithelial islands. These cells stain positively for S-100 protein, lysozome, MT 1, LN-3 and OKT 6 antibodies, but not for keratin antibody. Electronmicroscopic examination revealed the rod-shaped and racket-shaped structures called Birbeck's granules in the cytoplasm of these clear cells. Our observations indicate a variant case of CEOT with Langerhans cells in tumor nests.

Immunohistochemical localization of intermediate filament proteins in calcifying epithelial odontogenic tumors

Three calcifying epithelial odontogenic tumors (CEOT) were examined immunohistochemically. The localization of intermediate filaments was characterized through the use of polyclonal anti-keratin antiserum (TK which detects 41-65 kd keratins), 2 monoclonal keratin antibodies (PKK1 specific for the 44, 46, 52 & 53 kd keratins and KL1, specific for the 55-57 kd keratins) and monoclonal antibodies for vimentin and desmin. The tumor epithelial cells were slightly positive or negative for PKK1 detectable keratins, but slightly to strongly positive for KL1 and TK antibodies. Tumor epithelium was slightly positive for vimentin but negative for desmin. The tumor foci were composed of both dark-staining and pale-staining cells; the former had a more intense reaction with KL1 and TK antibodies than the latter. Homogeneous acellular material was either PAS-positive or negative, with or without calcification, and keratin-negative.

Intramural calcifying epithelial odontogenic tumor

The calcifying epithelial odontogenic tumor (CEOT) is a rare lesion of the jaws. It accounts for about 1% of all odontogenic tumors. The CEOT occurs primarily in the molar-premolar region of the mandible, and 52% of cases are associated with an unerupted tooth. This report describes an unusual case in a 37-year-old woman. The tumor arose in the molar area of the right mandible, appeared radiographically as a radiolucent lesion, and was thought to be a dentigerous cyst in association with an impacted first molar. The lesion was enucleated. Microscopic examination showed it to be a dental sac, within which were the 3 elements of a typical CEOT: squamoid cells with eosinophilic cytoplasm, the homogeneous eosinophilic substance, and calcium salt deposits in the form of Liesegang rings.

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.

Calcifying epithelial odontogenic tumours in three cats and a dog

Neoplasms histologically similar to calcifying epithelial odontogenic tumour (CEOT) of man are described in three cats and a dog. The diagnostic features of these neoplasms are their occurrence in the jaw and the histological appearance of cords of epithelial cells, amyloid spherules and foci of calcification. The histogenesis and behaviour of the tumour are discussed.

Identification of basement membrane components and intermediate filaments in calcifying epithelial odontogenic tumors

An immunohistochemical technique was used on paraffin-embedded tissues of four cases of calcifying epithelial odontogenic tumors (CEOT). These studies were performed to gain an additional understanding of the nature of amyloid-like deposits in these tumors. For these studies antibodies to Type IV collagen, laminin, and the five classes of intermediate filament proteins were employed. In all of the tumors examined basement membrane components and intermediate filament proteins (cytokeratin) were demonstrated both in the epithelial tumor islands and within the extracellular amyloid-like deposits. Antibodies to vimentin intermediate filaments were localized only in the stromal fibroblasts. Limited proteolysis or the use of a chaotropic agent was required to express the antigenic determinants present. These studies substantiate the presence of basement membrane components in the amyloid-like deposits of CEOT. In addition, these extracellular deposits are shown to be heterogenous in composition by the immunohistochemical demonstration of cytokeratin intermediate filament proteins.

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.

The nature of the amyloid-like material in a calcifying epithelial odontogenic tumour: an ultrastructural study

An ultrastructural study was carried out to investigate the nature of an eosinophilic material, having the staining properties of amyloid, in a case of calcifying epithelial odontogenic tumour. At the electron-microscopical level, the eosinophilic masses consisted of two types of structure which are probably related. The first type appeared as sheets of fine filaments measuring 10-12 nm in diameter. The second type was in the form of aggregates of lamina densa fragments, probably secreted by the tumour epithelium. These fragments appeared to undergo some loss of electron density and became degraded into fine filaments, having similar thickness and electron density to those forming the filamentous masses. It is concluded from this study that the fine filamentous material is a form of amyloid which results from degradation of lamina densa material.

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.

An investigation into the origin and nature of 'amyloid' in a calcifying epithelial odontogenic tumour

Fresh and fixed tissue from a resection specimen of a calcifying epithelial odontogenic tumour (CEOT) was prepared for histological, histochemical, immunological and biochemical investigation in order to study the nature of the amyloid-like material. The fixed tissue gave positive reactions with Congo-red, Thioflavin T and the dimethylamino benzene (DMAB)-method for tryptophan. The diazotization-coupling (DC) method for tyrosine was negative. The major protein purified from the unfixed tissue by sequential gel filtration had a molecular weight of 9,800. The amino acid analysis of this protein had similarities with tuft enamel protein, immune amyloid and the variable light chain component (VK). From the data obtained in this study, it is not possible to determine the precise nature of the amyloid-like material in this CEOT. However, the results do support the concept that 'amyloid' should be considered as a term describing a broad group of related proteins.

The calcifying epithelial odontogenic tumor. A review and analysis of 113 cases

A review of the world literature has revealed 113 cases of the calcifying epithelial odontogenic tumor. The clinical, radiographic, and histopathologic features are analyzed. Various treatments that have been carried out are related to the frequency of recurrence. The theories of histogenesis are discussed and an attempt is made to explain the nature and origin of the amyloid-like substance.

Calcifying epithelial odontogenic tumor (Pindborg tumor) case report

A 36-year-old woman was examined and treated for a rare odontogenic tumor in the mandible, the calcifying epithelial odontogenic tumor (CEOT), also known as the Pindborg tumor. The tumor extended from the left mandibular molar region to the right premolar area and had almost completely destroyed the bone in the anterior mandibular region. An orthopantomogram showed a multiloculated radiolucent lesion, with an unerupted tooth in the center surrounded by a radiopaque area. In addition, finely granular calcification was visible here and there in the tumor area. In the histologic examination the tumor tissue could be identified as calcifying epithelial odontogenic tumor. Under electron microscopy the fibrillar structure at the basal cell level suggested the presence of amyloid. The tumor was removed by enucleation with a collar of surrounding tissue. No signs of recurrence have been noted at follow-up examinations.

Calcifying odontogenic cysts with intracellular amyloid-like material

Intracellular deposits of amyloid as defined by positive Congo red staining with green polarization birefringence and standardized toluidine blue staining with pink-red polarization birefringence were observed in the epithelial lining of three cases of calcifying odontogenic cysts. It is suggested that this material is not true amyloid but, rather, a dengenerative product of the epithelial cells as has been described in calcifying epithelial odontogenic tumor (Pindborg tumor).

Ultrastructural study of amyloid material in the calcifying epithelial odontogenic tumor

A typical calcifying epithelial odontogenic tumor of the maxilla was examined with the electron microscope. The tumor cell resembles the ameloblast at an early stage of enamel deposition. Formation of extracellular amyloid masses probably proceeds both by active cellular secretion and cell death, each process adding similar granulofibrillar material to these masses, which tend to calcify. The amyloid masses are probably a relatively homogenous protein material and represent a specific tumor cell product. Further characterization of this neoplasm must include chemical and physical studies of this extracellular tumor product, which is an amyloid material because of classic staining characteristics.

Calcifying epithelial odontogenic tumor. A histologic, histochemical, fluorescent, and ultrastructural study

A previously unreported calcifying epithelial odontogenic tumor (CEOT; Pindborg tumor) occurring in a Negro patient is presented. Only 12 per cent of these neoplasms have been found in nonwhite patients. Ultrastructural and histochemical studies indicated that the amorphous, acellular, eosinophilic substance present within the tumor was not amyloid. The presence of only sparse calcifications is an unusual histologic variant. No relationship between neoplasm and reduced enamel epithelium could be demonstrated.