Non-calcifying Pindborg tumor with Langerhans cells

CD1a is not effective in distinguishing calcifying epithelial odontogenic tumors from amyloid-rich central odontogenic fibroma

OBJECTIVE

Differential diagnosis between the non-calcifying variant of calcifying epithelial odontogenic tumor (NCLC-CEOT) and amyloid-rich central odontogenic fibroma (AR-COdF) has become a debate, particularly regarding the frequency of CD1a positivity in both entities. This has led to the growing consensus that CD1a-positive staining in AR-NC lesions confirms the diagnosis of AR-COdF. Here, we assess the validity of this consensus.

STUDY DESIGN

We collected the data of a case series of histopathologically distinct CEOTs, NCLC-CEOTs, and COdFs and stained them for CD1a and amyloid. Of the 9 CEOTs and NCLC-CEOTs, we diagnosed 4 as classic, 3 as associated with a dentigerous cyst, and 2 as combined CEOT/adenomatoid odontogenic tumors. Of the 9 COdFs, we diagnosed 3 as epithelial poor, 3 as epithelial rich (lacking amyloid), 2 as hyalinized with amyloid, and 1 as hyalinized without amyloid and assessed the staining results.

RESULTS

Of the 9 CEOTs and NCLC-CEOTs, 7 stained positively for CD1a, 5 diffusely and 2 focally. Notably, 2 classic NCLC-CEOTs stained strongly CD1a positive. All 3 of the epithelial-poor COdFs were predictably CD1a negative. Of the 6 remaining COdFs, 2 were CD1a positive, 1 hyalinized-with-amyloid COdF diffusely and 1 epithelial-rich-without amyloid focally.

CONCLUSIONS

CD1a positivity, which occurs in classic CEOT and NCLC-CEOT, does not help distinguish between NCLC-CEOT and AR-COdF and is inconsistent in all AR-COdFs. The diagnosis of CEOT and AR-COdF should be guided by appropriate histopathologic criteria irrespective of CD1a staining or the presence of amyloid or calcifications.

Non-Calcifying/Langerhans Cell-Rich Calcifying Epithelial Odontogenic Tumour: A Critical Review of the Rare and Distinctive Entity

BACKGROUND

The study aims to analyse the non-calcifying/Langerhans cell rich (NCLC) subtype of calcifying epithelial odontogenic tumour (CEOT).  METHOD: The features of cases of the NCLC subtype of CEOT noted in the English literature by PubMed as well as 3 new cases were reviewed.

RESULTS

Overall, twenty-one cases were noted. Many were women in the fourth to sixth decades (male-to-female ratio =1 to 2). Radiologically, the lesion is often unilocular with resorption of the affected teeth. Nineteen of the 21 cases occurred in the maxilla, especially the anterior portion. On pathological examination, epithelial cells are noted in non-calcifying amyloid-rich fibrous stroma. The main differential diagnosis is the amyloid subtype of central odontogenic fibroma. Immunohistochemical studies revealed the tumour epithelial cells were positive for cytokeratins and p63 and contained CD1a, S-100, and langerin-positive Langerhans cells. On a median follow-up of 2 years, one patient had a recurrence one year after curettage.

CONCLUSION

The NCLC subtype of CEOT is unique as it contains significant numbers of Langerhans cells and has clinicopathological features distinctive from classic CEOT.

Noncalcifying type of calcifying epithelial odontogenic tumor: A rare case report and literature review

Key Clinical Message

There has been a recent spike in reporting of noncalcifying variants of CEOT with the WHO 2022 classification of head and neck tumors. The present case describes a rare histopathological variant of CEOT of which a handful of cases have been reported.

Abstract

This work aimed to report a rare case of noncalcifying type of Pindborg Tumor involving the right mandible. The absence of calcifications in the calcifying epithelial odontogenic tumor presents a diagnostic challenge and prognostic implications. A literature review of the 16 reported clinical cases of this scarce variant was performed.

Non-calcifying Langerhans Cell Rich Variant of Calcifying Epithelial Odontogenic Tumor and Amyloid Rich Variant of Central Odontogenic Fibroma: A Unique Entity or a Spectrum?

Overlapping clinicopathological features of non-calcifying Langerhans cell rich variant of calcifying epithelial odontogenic tumor (NCLC-CEOT) and the amyloid rich variant of the central odontogenic fibroma (AR-COF) have been recognized recently. It is still under debate whether these two diseases are indeed one unique disease entity or belong to CEOT and COF, respectively. To clarify this issue, we have performed a literature review to compare the similarities and differences in clinicopathological features among NCLC-CEOT, AR-COF, classic CEOT, and classic COF. We aimed to investigate whether NCLC-CEOT and AR-COF might be the same and one distinctive disease entity, or a variant (or variants) of either CEOT or COF; or whether COF, NCLC-CEOT/AR-COF, and CEOT represented a histopathological spectrum of one disease. Our results indicate that NCLC-CEOT and AR-COF cases share many similar clinicopathological features. Thus, we suggest that they are the same disease entity. Due to nearly no reported recurrence of NCLC-CEOT/AR-COF cases, the conservative surgical treatment is appropriate. The NCLC-CEOT/AR-COF cases show some overlapping clinicopathological features with COF rather than the CEOT cases. However, differences in the clinicopathological features are still recognized among the NCLC-CEOT/AR-COF, COF, and CEOT cases. Future research, particularly molecular biological studies, may further elucidate their relationships and assist proper classification of the NCLC-CEOT/AR-COF cases.

Noncalcifying clear-cell variant of calcifying epithelial odontogenic tumor: A case report and review

Clear-cell tumors of the head and neck are biologically diverse consisting of benign, malignant and metastatic lesions. These tumors pose a diagnostic challenge. In the oral cavity, these may be derived from odontogenic/nonodontogenic epithelium or from mesenchyme or can be metastatic. Odontogenic tumors with clear-cell change are rare. Calcifying epithelial odontogenic tumor (CEOT) is a rare, benign, locally aggressive odontogenic epithelial tumor affecting the jaw. Here, we report a case of clear-cell variant of CEOT with its histopathological differential diagnosis. A 43-year-old male patient with swelling in his lower right back tooth region showed a well-defined radiolucent lesion with smooth corticated periphery on radiograph. On incisional biopsy, tumor showed small sheets, cords and islands of odontogenic epithelium with nests of clear cells with no evidence of calcification. A final diagnosis of CEOT was established by differentiating other odontogenic and nonodontogenic lesions on the basis of clinical, radiographic, histopathologic and special stain features.

Calcifying epithelial odontogenic tumor: a case series spanning 25 years and review of the literature

OBJECTIVE

The calcifying epithelial odontogenic tumor (CEOT) is a rare benign neoplasm that makes up less than 1% of all odontogenic tumors. This study aims to describe a case series of CEOT spanning 25 years and to review and compare our results with the existing literature.

STUDY DESIGN

With institutional review board approval, all CEOT archival cases from the University of Florida Oral Pathology Biopsy Service between 1994 and 2019 were retrieved. A total of 20 cases were included. Based on current criteria, 2 cases that stained positively for CD1 a were excluded, because these most likely represented the amyloid-rich variant of central odontogenic fibroma.

RESULTS

Average patient age was 40 years. Females and males were affected equally (n = 10). The mandible was more commonly involved (60%, n = 12) than the maxilla (40%, n = 8). CEOT variants included incipient CEOT (10%, n = 2) and peripheral CEOT (10%, n = 2). One case exhibited features of adenomatoid odontogenic tumor in addition to CEOT. Congo red staining for amyloid was performed in 13 cases, all of which were positive.

CONCLUSION

Our results align with the literature. Awareness of the different variants of CEOT and of the separate but similar-appearing amyloid-rich variant of central odontogenic fibroma will help to ensure accurate diagnosis and appropriate treatment.

CEOT Variants or Entities: Time for a Rethink? A Case Series with Review of the Literature

The first detailed description of calcifying epithelial odontogenic tumor (CEOT) are ascribed to Jens Pindborg, but this tumor was described some years previously. Subsequently, CEOT was included in the 1971 WHO classification of odontogenic tumors and a since then number of variants have been described, which have added confusion to the diagnostic criteria. We aimed to survey the literature on the variants of CEOT, in parallel with a review of our single institution experience of CEOTs. Cases identified were collated, including available clinical, radiological and histological information and then reviewed, taking into account changes in the understanding and classifications of odontogenic tumors since initial diagnosis. We identified 26 cases from 1975 to 2017 for which histological material was available. Of these, only 13 (50%) showed the "classic" histological appearance, whilst two cases were identified as recognized variants. In 11 cases, other diagnoses or a differential diagnosis were preferred, with no agreed diagnosis in four of these. The proliferation fraction (Ki67) in the 10 cases tested was 2.1% ± 0.18. These findings illustrate the diagnostic challenges in this group of tumors and highlight the gaps in knowledge. Techniques, such as EWSR1 gene cytogenetic analysis, may be helpful in cases with clear cells. However, in other areas of controversy, including the non-calcifying and Langerhans cell rich variants, further investigation, perhaps utilizing sequencing technologies may be needed to refine the classification. Owing to the relative rarity of these lesions it would be beneficial if future work could be pursued as an international collaboration.

Non-calcifying Langerhans Cell-Rich Variant of Calcifying Epithelial Odontogenic Tumor: A Distinct Entity with Predilection for Anterior Maxilla

Calcifying epithelial odontogenic tumor (CEOT) is an uncommon locally invasive epithelial odontogenic tumor of the jaws associated with amyloid production. Intraosseous presentations are most common and they frequently occur in the posterior mandible. A non-calcifying Langerhans cell-rich variant of CEOT (NCLC CEOT) has been described with predilection for the anterior maxilla. Interestingly, all reported cases of NCLC CEOT have occurred in Asian population. We present a case of a 43-year old Caucasian female with a large radiolucent lesion involving the left anterior maxilla with histologic features of NCLC CEOT. This is the first reported case of this rare variant of CEOT in a Caucasian individual.

Non Calcifying Type of Calcifying Epithelial Odontogenic Tumor: An Unusual Case Report with Special Emphasis on Histogenesis of Calcifications

Calcifying epithelial odontogenic tumour also known as Pindborg tumour, is a rare benign odontogenic neoplasm of locally aggressive behavior. It is thought to arise from the epithelial element of the enamel origin which are reminiscent of the cells in the stratum intermedium layer of enamel organ in tooth development. The tumour is characterized histologically by the presence of polygonal epithelial cells, calcifications and eosinophilic deposits resembling amyloid. Non-calcifying epithelial odontogenic tumours are very rare and unusual. Only five cases have been reported in the English literature till date. Here, we present an additional case of non calcifying type along with a review of previously reported cases. It has a much lower recurrence and malignant transformation rate.

Non-calcifying and Langerhans cell-rich variant of calcifying epithelial odontogenic tumor

This study reported the clinicopathological features, treatment and prognosis of nine cases of noncalcifying and Langerhans cell (LC)-rich calcifying epithelial odontogenic tumor (CEOT) collected from the English literature. Of the nine cases, seven were intraosseous and two were extraosseous. All nine tumors were found in Asian patients. The age of the nine patients ranged from 20 years to 58 years with a mean age of 41 years. There were five female and four male patients. The seven intraosseous cases included six in the anterior and premolar region of the maxilla and one in the posterior region and ascending ramus of the mandible. The two extraosseous cases were located at the upper lateral incisor and premolar gingivae, respectively. Of the seven intraosseous cases, five showed unilocular and two multilocular radiolucency without foci of calcification. Six of the seven intraosseous cases showed resorption of the tooth roots in the tumor-involved region. Histologically, noncalcifying and LC-rich CEOTs were composed of small nests and thin strands of tumor epithelial cells with a relatively high number of LCs among them. This was the reason why we classed these nine cases as noncalcifying and LC-rich CEOTs. Two extraosseous cases received total excision of the gingival mass. For the seven intraosseous cases, four accepted partial maxillectomy or mandibulectomy, two received total excision or enucleation, and one underwent curettage. The six cases with the follow-up information available showed no tumor recurrence after a follow-up period of 6 months to 10 years.

Odontogenic Cysts and Tumors

This article presents various odontogenic cysts and tumors, including periapical cysts, dentigerous cysts, odontogenic keratocysts, orthokeratinized odontogenic cysts, lateral periodontal cysts, glandular odontogenic cysts, ameloblastomas, clear cell odontogenic carcinomas, adenomatoid odontogenic tumors, calcifying epithelial odontogenic tumors, squamous odontogenic tumors, ameloblastic fibromas, ameloblastic fibro-odontomas, odontomas, calcifying cystic odontogenic tumors, and odontogenic myxomas. The authors provide an overview of these cysts and tumors, with microsopic features, gross features, differential diagnosis, prognosis, and potential diagnostic pitfalls.

A rare case of hybrid odontogenic tumor: Calcifying epithelial odontogenic tumor combined with ameloblastoma

A hybrid odontogenic tumor comprising two distinct lesions is extremely rare. Nevertheless, such tumors have been reported in the literature for academic and research interest. However, it is still obscure whether they behave as a new entity or they solely present separate histopathologic patterns. Here, we present a true hybrid neoplasm of combined ameloblastoma and calcifying epithelial odontogenic tumor showing intermixed histopathologic patterns of both the tumors.

Current Concepts and Occurrence of Epithelial Odontogenic Tumors: II. Calcifying Epithelial Odontogenic Tumor Versus Ghost Cell Odontogenic Tumors Derived from Calcifying Odontogenic Cyst

Calcifying epithelial odontogenic tumors (CEOTs) and ghost cell odontogenic tumors (GCOTs) are characteristic odontogenic origin epithelial tumors which produce calcifying materials from transformed epithelial tumor cells. CEOT is a benign odontogenic tumor composed of polygonal epithelial tumor cells that show retrogressive calcific changes, amyloid-like deposition, and clear cytoplasm. Differentially, GCOTs are a group of transient tumors characterized by ghost cell presence, which comprise calcifying cystic odontogenic tumor (CCOT), dentinogenic ghost cell tumor (DGCT), and ghost cell odontogenic carcinoma (GCOC), all derived from calcifying odontogenic cysts (COCs). There is considerable confusion about COCs and GCOTs terminology, but these lesions can be classified as COCs or GCOTs, based on their cystic or tumorous natures, respectively. GCOTs include ameloblastomatous tumors derived from dominant odontogenic cysts classified as CCOTs, ghost cell-rich tumors producing dentinoid materials as DGCTs, and the GCOT malignant counterpart, GCOCs. Many authors have reported CEOTs and GCOTs variably express keratins, β-catenin, BCL-2, BSP, RANKL, OPG, Notch1, Jagged1, TGF-β, SMADs, and other proteins. However, these heterogeneous lesions should be differentially diagnosed to allow for accurate tumor progression and prognosis prediction.

A clinicopathologic study on calcifying epithelial odontogenic tumor: with special reference to Langerhans cell variant

BACKGROUND

Calcifying epithelial odontogenic tumour (CEOT) is a rare benign odontogenic tumour, and its Langerhans cell variant is even rarer. Due to the limited number of recorded cases, the biological behaviour and histogenesis of the Langerhans cell variant of CEOT are not yet fully understood. Thus, the correlation between conventional CEOT and the Langerhans cell variant remains to be clarified.

MATERIAL (CASES)

Eight cases of CEOT including 2 cases of Langerhans cell variant were clinicopathologically studied and the English language literature was reviewed. Langerhans cells were detected in 2 cases of conventional CEOT and in 2 cases of Langerhans cell variant by immunohistochemistry.

RESULTS AND FINDINGS

In the 6 cases of conventional CEOT, 5 tumours involved the premolar and molar region and the anterior portion of the mandible was affected in 1 case. Four patients were followed for 2-7 years and did not show any sign of recurrence. A review of the English language literature revealed 5 cases; combined with the present 2 new cases, a total of 7 cases of Langerhans cell variant of CEOT were collected. The patients were all Asian. Six tumours occurred in the maxilla and 1 in mandible; all mainly involved the anterior region of the jaws. Five patients were followed for 2-10 years and did not show any evidence of recurrence. Langerhans cells can be seen in both the conventional and the Langerhans cell variant of CEOT; however, increased numbers of Langerhans cells are seen in the latter.

CONCLUSIONS

Although the Langerhans cell variant of CEOT is a rare entity and behaves similarly to the conventional type, it could show unique clinical and histologic features that may pose problems for differential diagnosis.

VIRTUAL SLIDES

http://www.diagnosticpathology.diagnomx.eu/vs/1979090740113894.

Clear cell variant of calcifying epithelial odontogenic tumor without calcification: a rarity

Calcifying epithelial odontogenic tumor (CEOT) is a rare, benign, locally aggressive odontogenic epithelial tumor that affects the jaws. Although there are numerous reports on the variants of CEOT, occurrence of clear cells with complete absence of calcification has been a rarity. Histochemical analysis of tumor cells revealed glycogen granules with PAS staining, with absence of CD 1a staining in clear cells, while the amyloid-like deposit associated with clear cells showed green birefringence with Congo red. We report an unusual variant of CEOT occurring in a 27 years old male patient.

Calcifying epithelial odontogenic tumour with clear langerhans cells: a novel variant, report of a case and review of the literature

Clear cell calcifying epithelial odontogenic tumour (CCEOT) is a rare variant of calcifying epithelial odontogenic tumor (CEOT). While it is not surprising to find clear cells in odontogenic lesions, the exact nature of the clear cells in CCEOT has not been elucidated. Herein, we report a case of peripheral CCEOT of anterior mandible in a 37 year old black female. Histologically, the tumour consisted of cords and small nests of clear cells surrounded by dense deposits of amyloid and basophilic calcifications. The cells possessed abundant clear cytoplasm and eccentrically located indented nuclei. Admixed with the clear cells were eosinophilic cuboidal to polyhedral cells. The clear cells were PAS negative and immunoreactive for S100 protein, CD1a and Langerin. The clear cells were negative for MNF-116, SMA, Desmin and CK-19. It is therefore recommended to recognize two variants of CCEOT, namely, CEOT with clear cell change and CEOT with clear Langerhans cells (LC). We further suggest that the contradictory term "non-calcifying variant of calcifying epithelial odontogenic tumour with LC" to be abandoned, as the current case clearly indicates that LC could be seen in CEOT irrespective of the presence or absence of calcifications.

Clear-cell variant of calcifying epithelial odontogenic tumor (Pindborg tumor) in the mandible

We present an uncommon case (female patient aged 59 years) of the clear-cell variant of calcifying epithelial odontogenic tumor (CEOT) (also known as Pindborg tumor) in the mandible. The clinical characteristics and probable origins of the clear tumor cells of previously reported cases of clear-cell variant of intraosseous CEOT are also summarized and discussed.

CD1a-positive Langerhans cells and their relationship with E-cadherin in ameloblastomas and keratocystic odontogenic tumors

BACKGROUND

Ameloblastomas and keratocystic odontogenic tumors (KOTs) are lesions that are characterized by locally invasive growth and cause extensive bone destruction. In addition, it is known that E-cadherin influences the adhesion of Langerhans cells (LCs) to keratinocytes.

OBJECTIVE AND METHODS

The aim of this study was to investigate, using immunohistochemistry, the distribution of CD1a-positive cells in ameloblastomas and KOTs and their relationship with E-cadherin, in comparison to calcifying cystic odontogenic tumor (CCOT).

RESULTS

The CD1a-positive LCs were observed in 11 ameloblastomas and KOTs. All of the cases of CCOT showed CD1a-positive LCs and a significant difference was found when this tumor was compared with ameloblastomas (P < 0.05, Mann-Whitney test). A statistically significant difference was also noted when comparing CD1a-positive LCs between CCOTs and KOTs (P < 0.05, Mann-Whitney test). Lower expression of E-cadherin in ameloblastomas (AMs) in relation to KOTs and CCOTs (P < 0.05, Fisher test) was observed. There was no correlation between E-cadherin and CD1a-positive LCs between all odontogenic tumors that were studied (P > 0.05, Spearman test).

CONCLUSION

A quantitative difference of CD1a-positive cells between AMs and KOTs in comparison to CCOTs was observed. This permits to speculate that a depletion of CD1a-positive LCs might influence the local invasiveness of ameloblastomas and KOTs. Furthermore, it is suggested that E-cadherin mediates cell adhesion in these tumors.

Clear cell calcifying epithelial odontogenic (Pindborg) tumor involving the maxillary sinus: A case report and review of literature

Calcifying epithelial odontogenic tumor (CEOT) is a rare benign odontogenic neoplasm of the jaws, accounting for less than 3% of all odontogenic tumors. It rarely extends into the maxillary sinus. Till date, six cases involving maxillary sinus have been reported. In this paper, we report the seventh case of a 52-year-old male with CEOT in maxilla extending from distal surface of the right maxillary canine to retromolar area and involving maxillary sinus with no association with impacted teeth. The diagnosis was confirmed by aspiration cytology and histologically, the tumor was composed of sheets of epithelial cells, with areas of clear cell changes. The presence of clear cells in the histological sections, accounts for the aggressive nature of the tumor simulating the clinical appearance. Prevention of recurrence can be achieved by radical resection.

Calcifying epithelial odontogenic tumor (Pindborg tumor) without calcification: A rare entity

The calcifying epithelial odontogenic tumor is a rare benign odontogenic tumor that was first described by Pindborg in 1955. It accounts for less than 1% of all odontogenic neoplasms. The tumor is characterized histologically by the presence of polygonal epithelial cells, calcification, and eosinophilic deposits resembling amyloid. Noncalcifying Pindborg tumor is very rare and only three cases have been documented in the English language literature so far. We present an additional case of noncalcifying Pindborg tumor and review the previously reported cases. Because noncalcifying Pindborg tumor is believed to be an aggressive variant, a definitive resection of the tumor with tumor-free surgical margins and long-term follow-up is recommended.

Calcifying epithelial odontogenic tumor (Pindborg tumor)

The calcifying epithelial odontogenic tumor is a benign epithelial tumor with characteristic clinical and histopathologic features. These features are discussed with a typical case presentation along with emphasis on newer variants and management strategies.

[Benign epithelial odontogenic tumors]

The group of benign epithelial odontogenic tumors consists of the four member types of the ameloblastoma family (solid/multicystic, extraosseous/peripheral, desmoplastic, unicystic), squamous odontogenic tumors, calcifying odontogenic tumors, adenomatoid odontogenic tumors, and keratocystic odontogenic tumors, the former "keratocysts" that were recently reclassified by the World Health Organization and are now regarded as tumors. The latter are by far the most frequent tumors in this group, followed by solid/multicystic ameloblastoma. Although the etiology of these lesions is still unknown, a close relationship to normal tooth development is obvious, which is partially imitated by some tumors. Despite some similarities to each other, at least in part, the biological behavior of these lesions is quite different, as are treatment modalities. The diagnosis is essentially based on localization (intraosseous vs. extraosseous/peripheral) and histology, whereupon the correlation of histological findings with radiographic morphology may be of additional diagnostic value. Because of the range of variation, immunohistochemical investigations are not helpful in diagnosing a particular case.

Non-calcifying variant of calcifying epithelial odontogenic tumor with Langerhans cells

Calcifying epithelial odontogenic tumor (CEOT) is a rare type of odontogenic tumor. The most characteristic feature of the classical CEOT is the presence of amyloid globules and Liesegang ring calcification in the tumor tissue. Here, we present a non-calcifying variant of intraosseous CEOT with the presence of Langerhans cells within tumor epithelial nests in a 52-year-old Taiwanese woman. The patient was referred from a local dentist to our hospital for treatment of a unilocular radiolucent lesion at the right anterior region of the maxilla. The lesion was excised. Microscopically, the tumor was composed of small nests or strands of odontogenic epithelial cells and amorphous eosinophilic globules of amyloid-like materials in a loose fibrous connective tissue stroma. The tumor epithelial cells were positive for pan-cytokeratins (AE1 and AE3). Langerhans cells demonstrated by anti-CD1a staining were found in nests or strands of tumor epithelial cells. The eosinophilic globules were positive for Congo red and showed green birefringence when subjected to polarized light. Review of the English literature revealed two cases of non-calcifying variant of intraosseous CEOT with Langerhans cells in the anterior and premolar regions of the maxilla. Taken together, we suggest that the non-calcifying, Langerhan cell-rich variant of CEOT may have a distinct predilection for occurrence in the anterior and premolar region of the maxilla in contrast to the classical CEOTs that usually occur in the molar and ascending ramus area of the mandible.

Calcifying epithelial odontogenic tumor: an immunohistochemical case study

Calcifying epithelial odontogenic tumor (CEOT) is a rare benign odontogenic tumor. A case of CEOT in a 25-year-old female is presented here. Histologically, the case showed sheets of polyhedral epithelial cells with deep eosinophilic cytoplasm and prominent nuclei. Nuclear pleomorphism and hyperchromatism were evident. Globules of amyloid-like material among the tumor cells were prominent. Also found was a small area demonstrating a cribriform pattern. Immunohistochemical studies with antibodies against basement membrane proteins (laminins 1 and 5, collagen type IV and fibronectin), pan-cytokeratins AE1/AE3, vimentin, S-100 protein and CD 1a were performed. Tumor cells expressed laminins 1 and 5, fibronectin, cytokeratins and vimentin. The amyloid-like material was not reactive to all antibodies examined. A number of dendritic cells among sheets of tumor cells were revealed with strong staining for S-100 protein and CD 1a. These dendritic cells are likely to be Langerhans cells. Hence, immunohistochemistry is a useful method to study the variant of CEOT.

Calcifying epithelial odontogenic (Pindborg) tumor-associated amyloid consists of a novel human protein

Calcifying epithelial odontogenic tumors (CEOTs), also known as Pindborg tumors, are characterized by the presence of squamous-cell proliferation, calcification, and, notably, amyloid deposits. On the basis of immunohistochemical analyses, the amyloidogenic component had heretofore been deemed to consist of cytokeratin-related or other molecules; however, its chemical composition had never been elucidated. We have used our microanalytic techniques to characterize the protein nature of CEOT-associated amyloid isolated from specimens obtained from 3 patients. As evidenced by the results of amino-acid sequencing and mass spectrometry, the fibrils were found to be composed of a polypeptide of approximately 46 mer. This component was identical in sequence to the N-terminal portion of a hypothetical 153-residue protein encoded by the FLJ20513 gene cloned from the human KATO III cell line. That the amyloid protein was derived from this larger molecule was demonstrated by reverse transcription-polymerase chain reaction amplification of tumor-cell RNA where a full-length FLJ20513 transcript was found. Furthermore, immunohistochemical analyses revealed that the amyloid within the CEOTs immunostained with antibodies prepared against a synthetic FLJ20513-related dodecapeptide. Our studies provide unequivocal evidence that CEOT-associated amyloid consists of a unique and previously undescribed protein that we provisionally designate APin.

Clear-cell variant of calcifying epithelial odontogenic tumor: clinical and radiographic characteristics

OBJECTIVES

Clear cells have been reported in approximately 8% of cases of calcifying epithelial odontogenic tumor (CEOT). The purpose of this study was to describe the clinical and radiographic features of clear-cell CEOT (CCEOT).

STUDY DESIGN

Eighteen cases of CCEOT were identified by review of the literature from 1958 to 2001, and a new one was added (total 19; 12 central, 7 peripheral).

RESULTS

Fourteen tumors (74%) were located in the mandible, with the central lesions favoring the posterior area and the peripheral lesions the anterior-bicuspid area. Radiographic features were as follows: 50% radiolucent, 50% mixed radiolucent-radiopaque; 92% unilocular; 64% well-defined noncorticated borders, 27% well-defined corticated borders, 9% irregular borders. Cortical perforation was common (67%) compared with CEOT without a clear-cell component (6.7%). Recurrence was reported in 17% of the central lesions and none of the peripheral ones.

CONCLUSIONS

CCEOT is a distinct variant of CEOT; its high tendency for cortical perforation may indicate a more aggressive behavior.

Peripheral clear cell variant of calcifying epithelial odontogenic tumor: Report of a case and immunohistochemical investigation

A case of peripheral calcifying epithelial odontogenic tumor, clear cell variant, located on the right gingival maxilla of a 48-year-old woman, presenting as a 2.0-cm solitary, firm nodule was studied. Microscopically, it was composed of polyhedral and clear epithelial cells associated with amyloid-like deposition. The clear epithelial cells exhibited granules that were positive for periodic acid-Schiff, and the amyloid-like deposit stained with Congo red showed a green birefringence in the polarized light. Polyhedral and clear epithelial cells were immunopositive for AE1/AE3 and cytokeratin 14. Immunoexpression of fibronectin and types I and III collagen were different between the amyloid-like deposits and the connective tissue stroma. Tenascin surrounded epithelial cells located inside the amyloid-like deposits. Laminin and type IV collagen were immunodetectable around the strands, cords, and nests of epithelial cells. This report represents the seventh case of peripheral calcifying epithelial odontogenic tumor, clear cell variant.

Calcifying epithelial odontogenic tumor showing microscopic features of potential malignant behavior

Calcifying epithelial odontogenic tumor (CEOT) is a rare benign, but locally aggressive, odontogenic tumor, and only 2 cases of malignant CEOT are reported in the literature. We describe a case of an atypical CEOT that penetrates the blood vessels, invades bone, and perforates the cortical plates of the mandible. On histologic examination, it shows marked pleomorphism and numerous mitotic figures, including a tripolar mitotic figure. Proliferating activity was found to be 5 times higher than typical CEOTs as demonstrated by the proliferating index, Ki-67, and analyzed by a computerized image analysis system. The Ki-67 labeling index of this case was also compared to various previously reported benign and malignant neoplasms. Although there is no clinical finding of metastasis, we believe this neoplasm has malignant potential on the basis of the histologic features of vascular invasion, significant mitotic activity, atypical mitotic figures, and an increased proliferating index.

Calcifying epithelial odontogenic tumor with intracranial extension: report of a case and review of the literature

The calcifying epithelial odontogenic tumor (CEOT) is a rare benign neoplasm, possibly of stratum intermedium origin and occurring predominantly in the mandible of adults. The treatment varies, depending on its size, location, and histology. A case of an advanced CEOT arising in the maxilla with intracranial extension is reported. The report is supplemented by a review of the literature.

Immunohistochemical detection and distribution of enamelysin (MMP-20) in human odontogenic tumors

Enamelysin is a tooth-specific protease that was initially isolated from porcine enamel organ and subsequently from human odontoblasts. Since this protease is thought to play important roles in tooth development, the evaluation of enamelysin in odontogenic tumors may aid our understanding of the histogenesis and cell differentiation of such lesions. A monoclonal antibody (203-1C7) was generated against synthesized human enamelysin oligopeptide and was used to assess the immunolocalization of enamelysin in healthy developing tooth germs and various types of odontogenic lesions. In tooth germs, enamelysin expression was detected only in the secretory enamel. Thus, 203-1C7 may serve as an enamel-specific marker in the late stage of enamel matrix development and calcification. In odontogenic lesions, strong enamelysin staining was demonstrated in the immature enamel matrix of ameloblastic fibro-odontomas and odontomas. Furthermore, enamelysin was also detected in globular amyloid masses and calcified foci in calcifying epithelial odontogenic tumors, hyaline droplets, small and large mineralized areas in adenomatoid odontogenic tumors, and a portion of ghost cells in calcifying odontogenic cysts. Positive reactivity was also observed in selected tumor cells in some of these tumors. No intracellular staining for enamelysin was detected in ameloblastomas or the ameloblastic portion of ameloblastic fibro-odontomas. Also, enamelysin was not detected in dentin, dysplastic dentinoid hyaline matrices, and cementum that were present within the tumors examined. Thus, taken together, our results suggest that the enamelysin-specific monoclonal antibody (203-1C7) may be utilized as a marker of early enamel development and that enamelysin may be involved in the pathogenesis of specific odontogenic tumors.

Peripheral clear cell calcifying epithelial odontogenic tumor. Report of a case

Calcifying epithelial odontogenic tumor (CEOT) is an uncommon, locally aggressive odontogenic tumor representing less than 1% of all odontogenic tumors. Clear cells have been described in CEOT, ameloblastomas, calcifying odontogenic cysts, lateral periodontal, and gingival cysts. It is not yet clear if the clear cell variants of the odontogenic tumors have a different biologic behavior, even if it seems that these tumors are more aggressive with an higher recurrence rate. The authors present a case of a peripheral clear cell CEOT (CCCEOT). It is a rare lesion with only 9 cases reported in the literature. The lesion was removed by excision and no recurrence was found after a 4-year follow-up.

Calcifying epithelial odontogenic tumour: biological profile based on 181 cases from the literature

The present profile of the calcifying epithelial odontogenic tumour (CEOT) is based on a literature survey of 181 published tumour cases. The CEOT is a benign, though occasional locally invasive, slow-growing neoplasm occurring as intraosseous (94%) and extraosseous (6%) variants. The intraosseous type appears radiographically as an irregular, uni- or multilocular radiolucent area containing radiopaque masses which increases in size and opacity with time. Some 60% of intraosseous CEOT are associated with an unerupted tooth (or odontoma). CEOT shows a relative frequency of 1-2%. The extraosseous variant is diagnosed slightly earlier (mean age 34.4 years) than the intraosseous type (mean age 38.9 years). Both variants have an almost 1:1 gender ratio. The intraosseous CEOT shows a maxilla:mandible site ratio of 1:2 and are mainly located in the premolar/molar region. The present authors present evidence that the CEOT originates from the complex system of dental laminae or remnants thereof. Histologically, the CEOT is characterized by the occurrence of sheets, nests and masses of polyhedral, eosinophilic epithelial cells which may show cellular abnormalities including giant cell formation and nuclear pleomorphism. Some cells increase in size and produce a homogeneous, eosinophilic, 'amyloid-like' substance which may become calcified and which may be liberated as the cells break down. The true nature of the amyloid-like material is still unresolved. Histological variants including CEOT with cementum-like components, clear-cell CEOT (15 cases reported so far), CEOT-containing Langerhans' cells, combined epithelial odontogenic tumour (CEOT/AOT) and CEOT with myoepithelial cells are discussed in detail. In view of the relatively indolent biological behaviour of the CEOT, mutilating procedures, such as wide resection or hemisection of the mandible, seem unwarranted. Enucleation with a margin of macroscopically normal tissue is, therefore, the recommended treatment for CEOT involving the mandible. Maxillary CEOT should, however, be treated more aggressively, as they tend to grow more rapidly and do not usually remain well confined. Generally, recurrences are rare. Five years is considered the absolute minimum follow-up period. The survey has revealed only one well-documented case of a mandibular CEOT in a 75-year-old man showing features of malignancy.

Clear cell variant of calcifying epithelial odontogenic tumor (CEOT) in the maxilla: report of a case with immunohistochemical and ultrastructural investigations

A rare case of clear cell variant of calcifying epithelial odontogenic tumor is presented with immunohistochemical and ultrastructural investigations. A 14-year-old Japanese girl was admitted with a complaint of swelling in the right posterior maxilla. Radiological examination showed a well-circumscribed radiolucent lesion located close to the impacted third molar. After only a partial tumor excision, the tumor recurred 13 years later. It appeared radiologically as an irregular radiodensity, and a subtotal maxillectomy was performed. Histological examination showed sheets and/or strands composed almost entirely of clear vacuolated epithelial cells in a stroma containing intercellular amyloid-like material and calcification. Histochemical and ultrastructural analysis detected cytoplasmic glycogen granules in the clear cells, and positive immunoreactivities for cytokeratins 8, 13 and 19; filaggrin and anti-ameloblastoma antibodies suggested an odontogenic epithelial origin.

Clear cell odontogenic carcinoma in the mandible: histochemical and immunohistochemical observations with a review of the literature

A rare case of clear cell odontogenic carcinoma was investigated using histochemical and immunohistochemical methods. The tumor occurred in the anterior mandible of a 69-year-old Japanese man. Histologically, the tumor was composed mostly of large clear cells and squamous cells. Columnar-shaped cells with basophilic nuclei polarized away from the basement membrane were observed at the periphery of the tumor foci. The tumor cells had aggressively invaded muscle and perineural tissues. The tumor cells were positive for PAS staining. Immunohistochemically, tumor cells reacted positively to keratin, cytokeratin19, epithelial membrane antigen, and S-100 protein. The tumor was diagnosed as a clear cell odontogenic carcinoma. Its characteristics are discussed in term of its histopathological, histochemical and immunohistochemical features.

A clinicopathological and immunohistochemical study of the calcifying epithelial odontogenic tumour (Pindborg tumour) in Malaysians

We reviewed the clinicopathological characteristics of 13 cases of calcifying epithelial odontogenic tumour (CEOT) (Pindborg tumour) diagnosed in the Division on Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year period. There were eight female and five male patients. These consisted of eight (61.5 per cent) Malays, three (23.1 per cent) Chinese, one (7.7 per cent) Indian and one (7.7 per cent) Melanau. Their ages at presentation ranged from 19-61 years (mean age, 31.8 years). There were 12 central and one peripheral CEOT. Of these, 76.9 per cent of cases were located in the maxilla, the remaining in the mandible. The commonest clinical diagnosis was a dentigerous cyst (66.7 per cent). Enucleation was the main mode of treatment. Histologically, sheets and strands of polyhedral epithelial cells containing eosinophilic, homogeneous globules with Liesegang rings were observed. One case also showed extensive calcification and clear cell differentiation. Immunohistochemistry revealed a variable keratin staining of the CEOT epithelium, confirming its heterogeneity.