Clear-cell ameloblastoma (clear-cell odontogenic carcinoma): report of a case

Exuberant clear cell odontogenic carcinoma of the mandible harboring EWSR1 rearrangement: Report of a rare case and a literature review

Clear cell odontogenic carcinoma (CCOC) is a rare malignant odontogenic tumour (MOT) that mainly affects the mandible, with a slight female predominance in adult patients. In this study, we described an exuberant CCOC in mandible of a 22-year-female patient. On radiographic examination, a radiolucent lesion in the region of tooth 36 to 44 with tooth displacement and alveolar cortical resorption was observed. Histopathological study revealed a malignant neoplasm of the odontogenic epithelium, composed of PAS-positive clear cells and immunoreactivity for CK5, CK7, CK19, p63. The Ki-67 index was low (<10 %). Fluorescent in situ hybridization revealed EWSR1 gene rearrangement. The diagnosis of CCOC was established and the patient was referred for surgical treatment.

Clear Cell Odontogenic Carcinoma a Systematic Review

Clear cell Odontogenic Carcinoma (CCOC) is an uncommon malignant odontogenic tumor (MOT). It is the fifth most common MOT. A systematic review is presented of reported cases, case series and retrospective studies of CCOC, to determine trends in presentation, diagnostic features, treatment, and patient outcome. Searches of detailed databases were carried out to identify papers reporting CCOC. The variables were demographics, patient symptoms, tumor location, histopathological findings, immunohistochemical studies, treatment, follow-up, and recurrence. 117 cases were identified; CCOC was most frequently seen in mature females 65% (n = 76). The total average age was 55.4 with a range from 17 to 89 years, for females 56.4 and males 53.6 years. The mean size was 3.41 cm. The most common location was in the mandibular body 36.2% (n = 42), followed by the anterior mandible 23.3% (n = 27). The most common clinical presentation was a swelling 80.4% (n = 74), and the main symptom was pain 41.3% (n = 31), followed by painless lesion 24% (n = 18). The most common Immunohistochemistry positive expression was CK19, EMA, and CEA, and for special staining periodic acid Shiff (PAS); 97% of cases were treated surgically. The average follow-up was 30.3 months, and recurrence was reported in 52.4% of the cases. Conclusion: CCOC shows a strong predilection for the body and anterior mandible, and females are more frequently affected. CCOCs can be painful and the principle clinical sign is swelling, CCOCs can metastasize, and the prognosis is fair.

Rare clear cell odontogenic carcinoma associated with impacted tooth in a young patient: case report and literature review

Clear cell odontogenic carcinoma (CCOC) is a rare malignant odontogenic tumor. It is characterized by showing, on histopathological examination, clusters of vacuolated and clear tumor cells with epithelial differentiation surrounded by fibrocollagenous stroma and fibroblasts. The present study presents a rare clinical case of mandibular CCOC associated with an impacted tooth in a 26-year-old woman surgically treated with mandibulectomy and reconstruction with iliac crest bone graft. The patient has been followed up for 22 months without signs of recurrence. A search for case report/case series was carried out in the PUBMED database, as well as in the references of relevant previously published literature reviews. Ninety-six publications were identified, totaling 136 distinct cases reported. Female sex was the most affected (63.1%) with 63.3% of cases occurring in patients in the fifth, sixth, or seventh decades of life. The mandible was more affected than the maxilla (74.2%). Association of CCOC with impacted teeth was found in 2.4% of cases, thus rendering it a rare occurrence. The present case report corroborates the results of the survey regarding sex and anatomical location of the tumor; however, it contradicts the findings regarding age predilection. The case described is the fourth known occurrence of tooth impaction associated with the tumor and the first in a female. In conclusion, CCOC should be considered, as well as other malignancies, as a possible diagnosis of maxillary or mandibular intraosseous lesions even in unusual circumstances such as in association with impacted teeth and in young patients.

Pathogenesis and characteristics of large ameloblastoma of the jaw: a report of two rare cases

Ameloblastoma is a common odontogenic epithelial tumor that exhibits various biological behaviors, ranging from simple cystic expansion to aggressive solid masses characterized by local invasiveness, a high risk of recurrence, and even malignant transformation. We report on two cases of unusually large solid ameloblastomas. We detected epithelial–mesenchymal transition-related gene expression and HRAS gene single nucleotide polymorphisms, providing possible molecular evidence of mesenchymal morphological changes in ameloblastoma. The detailed analysis of the pathogenesis of these two cases of ameloblastoma may deepen our understanding of this rare disease and offer promising targets for future targeted therapy.

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.

Odontogenic Carcinoma With Dentinoid in Long-Term Follow-up With 2 Recurrences

Dentinoid has been mentioned as a frequent component in several types of benign odontogenic tumors; however, there are some other very rare dentinoid-producing odontogenic tumors that have been described, which are not recognized in the current World Health Organization Histological Classification of Odontogenic Tumours. In this context, we report an unusual malignant odontogenic tumor containing dentinoid located in the left maxilla of a 41-year-old man. The lesion was initially diagnosed and treated as a cemento-ossifying fibroma. After 7 years, a tumor was noted at the same location and was diagnosed as pleomorphic adenoma. The patient developed a new lesion 2 years later. Histological features included an epithelial proliferation of basaloid and clear cells, some with peripheral palisading, which were scattered both in a fibrous stroma and within an amorphous eosinophilic dentinoid product. Because of doubts about the first 2 diagnoses and the current situation, all histopathological slides were reviewed in our service as a consultation case, and the findings were consistent with the diagnosis of an odontogenic carcinoma with dentinoid. Immunohistochemical analysis was performed and an ultrastructural study by scanning electronic microscopy and energy-dispersive X-ray microanalysis was made to characterize dentinoid material. After 1 year of follow-up, the patient is alive and free of the disease. This case highlights the wide variability regarding cytological evidence of malignancy, and adds a new case of odontogenic carcinoma with dentinoid, which represents a distinct entity with locally aggressive behavior and should be considered be included in a future World Health Organization Histological Classification of Tumours.

Clear cell odontogenic carcinoma: a rare jaw tumor. A summary of 107 reported cases

The purpose of this study was to summarize the currently published cases of clear cell odontogenic carcinoma (CCOC). The PubMed and Springer databases were used to collect available reports, searching for 'clear cell odontogenic carcinoma', 'CCOC', or 'clear cell ameloblastoma'. The search resulted in 75 reports detailing 107 cases between 1985 and 2018. Clinically the tumor manifests as a swelling in the posterior mandible (n=46), anterior mandible (n=33), and maxilla (n=28). Radiological analysis of 85 cases typically showed a poorly defined expansive radiolucency (n=83). Of the 70 patients with symptoms reported, 44 specified a swelling, 11 tooth mobility, seven gingival/periodontal issues, five numbness, and three decreased jaw opening. One patient presented with a neck mass. The duration of symptoms prior to seeking care was specified for 52 patients: 2 months to 1 year for 34 patients, 1-2 years for seven, 2-4 years for two, 4-7 years for six, and 7-12 years for three. The incidence of recurrence appeared to be 38 of the 88 cases where recurrence was reported. CCOC can be distinguished from other oral cancers by its distinctive histology and immunohistochemical characteristics and less aggressive behavior. Currently, treatment should be early and aggressive resection with clear surgical margins and long-term follow-up. The overall goal is to collect a cohort of patients.

Clear cell odontogenic carcinoma of the mandible: a treatment strategy

Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic tumor of the jaws, histologically characterized by the presence of agglomerates of cells with eosinophilic cytoplasm. The patient, a 62-year-old Caucasian woman, presented an intraosseous lesion in the mandibular symphysis. A clinical examination revealed a discrete volumetric increase with a hard consistency, palpable to extraoral and intraoral examinations. Imaging studies revealed an extensive radiolucent area, without defined limits, extending from the region of the right second premolar to the left canine. Incisional biopsy analysis indicated a diagnosis of CCOC. The treatment proposed was segmental resection of the mandible with a safety margin. After six months without recurrence, definitive mandibular reconstruction was performed using an iliac crest graft, followed by rehabilitation with implant-supported denture after five months. After three years of post-resection follow-up, the patient has shown no evidence of recurrence or metastasis. She continues to be under follow-up. To conclude, CCOC must be considered a malignant tumor with aggressive behavior. Previous studies have shown that resection with free margins is a treatment with a lower rate of recurrence. Nevertheless, long-term follow-up is necessary for such patients.

The role of computed tomography and magnetic resonance imaging in diagnosing clear cell ameloblastoma: A case report

Ameloblastoma is the most common and clinically relevant type of odontogenic tumor. Clear cell odontogenic carcinoma is histologically characterized by solid sheets and nests of clear cells, whereas clear cell ameloblastoma (CCAM) is histologically characterized by an ameloblastomatous component intermixed with an extensive clear cell component. A total of 12 reports have been published on the histological etiology for CCAM; however, no reports have made regarding the detailed computed tomography and/or magnetic resonance imaging features of tumors of this type. The present study describes a case of a well-circumscribed 20-mm radiolucent lesion of the anterior mandible that was misdiagnosed as a clear cell odontogenic carcinoma. The study describes the detailed radiological characteristics of a case of CCAM.

Odontogenic Cysts and Neoplasms

This article reviews a myriad of common and uncommon odontogenic cysts and tumors. The clinical presentation, gross and microscopic features, differential diagnosis, prognosis, and diagnostic pitfalls are addressed for inflammatory cysts (periapical cyst, mandibular infected buccal cyst/paradental cyst), developmental cysts (dentigerous, lateral periodontal, glandular odontogenic, orthokeratinized odontogenic cyst), benign tumors (keratocystic odontogenic tumor, ameloblastoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor, ameloblastic fibroma and fibroodontoma, odontoma, squamous odontogenic tumor, calcifying cystic odontogenic tumor, primordial odontogenic tumor, central odontogenic fibroma, and odontogenic myxomas), and malignant tumors (clear cell odontogenic carcinoma, ameloblastic carcinoma, ameloblastic fibrosarcoma).

Clear cell odontogenic carcinoma: report of 7 new cases and systematic review of the current knowledge

OBJECTIVE

The goal of this study is to describe 7 cases of clear cell odontogenic carcinoma among a Brazilian population and compare these data with a systematic review of the English-language literature.

STUDY DESIGN

Descriptive statististics were used to compare the clinicopathologic data gathered retrospectively with those compiled from a review. Tumor sections were immunostained for Ki-67, p16, p53, and cytokeratins (CKs) 7, 8, 14, 18, and 19. Log-rank tests were performed for survival analysis.

RESULTS

Most cases occurred in the posterior mandible (5/7, 71.4%), and recurrence was diagnosed in all treated patients. Metastatic disease occurred in 2 patients (28.6%). Tumors were focally positive for CKs 7, 8, 14, and 18 and diffusely positive for CK19, p53, and p16. The mean number of Ki-67-positive cells was 35.2 cells/high-power field. Our systematic review provided evidence that tumor size (P = .046), histologic pattern (P = .034), regional metastasis (P = .001), distant metastasis (P = .001), and local recurrence (P = .05) were of significant prognostic value.

CONCLUSIONS

This study has contributed to improved characterization of clear cell odontogenic carcinoma, which is an aggressive odontogenic malignant neoplasm diagnosed mainly in the posterior mandible of middle-aged women and typically at an advanced stage. Radical surgical procedures remain the gold standard treatment.

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 odontogenic carcinoma of maxilla: A case report and mini review

Clear cell odontogenic carcinoma is a rare odontogenic tumor occurring predominantly in posterior mandible during 5^th-7^th decades with a female predilection. It is a potentially aggressive tumor, capable of frequent recurrences and loco-regional and distant metastases. Till date, only 73 cases have been reported in the literature. Current case is of a 55-year-old woman with tumor mass extending from canine to molar region on the left maxillary arch. Being locally aggressive tumor with the capacity to metastasize, it demands to be distinguished from other primary and metastatic clear cell tumors of the oral and maxillofacial region. A brief compilation of the reported cases is being attempted in the current article to better understand the behavior of the tumor.

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.

Clear Cell Tumors of the Head and Neck: An Overview

Clear cells are routinely encountered in the histopathological sections. They most frequently result from fixation artefacts; cytoplasmic accumulation of water, glycogen, lipids, mucins; hydropic degeneration of organelles, etc. When these clear cells predominate in a tumor, arriving at a definitive diagnosis becomes problematic. Thus, this review gives an idea of clear cells associated with various conditions, causes for clearing of these cells, clear cell tumors of the head and neck and a systematic approach towards arriving at an appropriate diagnosis of these tumors.

How to cite this article

Premalatha BR, Rao RS, Patil S, Neethi H. Clear Cell Tumors of the Head and Neck: An Overview. World J Dent 2012;3(4):344-349.

Clear cell carcinoma and clear cell odontogenic carcinoma: a comparative clinicopathologic and immunohistochemical study

Clear cell carcinoma or hyalinizing clear cell carcinoma (CCC) and clear cell odontogenic carcinoma (CCOC) are rare, low-grade and typically indolent malignancies that can be diagnostically challenging. In this study the clinicopathologic, histologic, and immunohistochemical features of 17 CCCs and 12 CCOCs are examined. The differential diagnosis of clear cell malignancies in the head and neck is discussed. The relationship of CCCs and CCOCs to other clear cell tumors on the basis of their immunohistochemical staining patterns is postulated.

Clear cell unicystic ameloblastoma

Clear cell differentiation in unicystic ameloblastoma with inclusion of many other histologic variants in the same tumor is a very rare occurrence. Here, we report a case of a well-circumscribed large mandibular swelling in a 22 - year old female. The lesion was histopathologically diagnosed as unicystic ameloblastoma which showed multiple histologic patterns and clear cell differentiation. The tumor was treated with surgical enucleation and chemical cauterization. A follow up of 20 months has shown no recurrence after initial surgery.

Clear cell odontogenic carcinoma: case report with immunohistochemical findings adding support to the challenging diagnosis

Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic tumor associated with aggressive clinical behavior, metastasis, and low survival. We report a case of CCOC affecting the mandible of a 39-year-old man. The tumor presented a biphasic pattern composed of clear cell nests intermingled with eosinophilic cells and separated by collagenous stroma. Immunoreactivity to cytokeratin (CK), specifically AE1/AE3 and CK 8, 14, 18, and 19 was found, as well as to epithelial membrane antigen (EMA). The tumor cells were negative for S100 protein, CK 13, vimentin, smooth muscle actin, laminin and type IV collagen. Low labeling indices for the proliferation markers Ki-67 and proliferating cell nuclear antigen and to p53 protein might predict a favorable prognosis for the lesion. A surgical resection was performed, followed by adjuvant radiotherapy. A 2-year follow-up has shown no signs of recurrence. The significance of histochemical and immunohistochemical resources in the correct diagnosis of CCOC is analyzed.

Clear cell odontogenic carcinoma of the maxilla: a case report and literature review

BACKGROUND

Clear cell odontogenic carcinoma (CCOC) is a rare tumor of odontogenic origin. It was first described as a clinicopathological entity in 1985, and since then, several case reports have been published.

METHODS

We present a patient with CCOC treated at the University of Florida and review the pertinent literature.

RESULTS

We treated a 52-year-old woman with CCOC of the maxilla. She received a maxillectomy and postoperative radiotherapy (RT). She developed pulmonary metastases 2 years after treatment. She remains alive and asymptomatic 7 years after completing treatment and has not required additional therapy. The literature search yielded 48 other case reports. The median age at presentation was 53 years (mean, 55 years), the female-to-male ratio was 2:1, and the most common site of presentation was the mandible. Three patients presented with submandibular lymphadenopathy. Most patients had a surgical resection (35 patients, 71%); the remainder underwent curettage. Six (12%) patients received postoperative RT. Eighty percent of patients who were initially treated with curettage developed a local recurrence. Local and/or regional recurrences occurred in 34% of patients who underwent surgical resection. Six patients developed distant metastatic disease; the most common site of the metastases was the lung. Seven patients died from or with the disease, and 3 are alive with the disease.

CONCLUSIONS

Clear cell odontogenic carcinoma is a rare tumor of the mandible and maxilla that has the propensity for local destruction and the potential for lymphatic and hematogenous metastases. We recommend radical excision as the primary treatment and that adjuvant RT be added for those who have close or positive margins as well as those with lymph node metastases.

Ameloblastic carcinoma: An analysis of 14 cases

OBJECTIVES

To present the classifications of malignant ameloblastomas, provide histopathologic guidelines for the diagnosis of ameloblastic carcinoma, and discuss treatment and long-term follow-up.

STUDY DESIGN

Fourteen archival specimens of ameloblastic carcinoma with detailed treatment and follow-up documentation were identified by the authors.

RESULTS

Traditional methods of microscopic observation form the basis for diagnosis. Histopathologic features of ameloblastic carcinoma include lack of differentiation, hypercellularity, high mitotic index, vascular invasion, and neural invasion.

CONCLUSION

The long-term follow-up findings in this study support the concept that aggressive surgical intervention provides the best chance for survival. Patients treated otherwise had recurrence. The patients with the highest number of recurrences did not survive the disease.

Clear cell odontogenic carcinoma: a comprehensive analysis of treatment strategies

BACKGROUND

Odontogenic neoplasms of predominately clear cells are unusual. They represent a diagnostic dilemma, and as a result, treatment strategies are diverse. Our goal is to present two new cases, summarize reported cases of clear cell odontogenic carcinoma (CCOC), assess potential risk factors for recurrence, and propose definitive surgical and therapeutic strategies.

METHODS

A literature search and analysis was performed. Regression models were used to predict risk factors for recurrence.

RESULTS

Forty-three cases of CCOC were reviewed, including two reported here. The overall rate of recurrent disease was 55%. Local recurrence rates were higher for curettage (80%) than for resection alone (43%). Age (p = .20), sex (p = .28), and tumor site (p = .50) did not predict risk for recurrence.

CONCLUSIONS

CCOC is a potentially aggressive tumor with a tendency for recurrence. Treatment strategies should be directed toward wide surgical resection with confirmation of tumor-free margins. Lymph node dissection and adjuvant radiation therapy should be considered in selected cases.

Clear cell odontogenic carcinoma and clear cell ameloblastoma: a single clinicopathologic entity? A new case and comparative analysis of the literature

BACKGROUND

Clear cell odontogenic carcinoma (CCOC) is histologically characterized by solid sheets and nests of clear cells. Clear cell ameloblastoma (CCAM) is histologically characterized by an ameloblastomatous component intermixed with an extensive clear cell component. In all literature reviews, no separation has been made between the clinicopathologic features of CCOC and CCAM.

PURPOSE

We sought to review and analyze the clinicopathologic and radiologic features and the biologic behavior of CCOC and to compare them with those of CCAM to evaluate the possible separation between the 2 lesions.

MATERIALS AND METHODS

A MEDLINE search of the English-language literature was carried out for CCOC and CCAM. Cases were classified according to their histologic features.

RESULTS

A total of 27 cases of CCOC (26 from the literature and 1 new case) and 8 cases of CCAM were found. CCOC patients showed a male-to-female ratio of 1:2.4, with a mean age of 59 years. CCAM patients showed a male-to-female ratio of 1.7:1, with a mean age of 44 years. CCOC and CCAM were predominantly found in the mandible. Both CCOC and CCAM showed a high rate of recurrence (50% and 63%, respectively) and metastases (33% and 25%, respectively). Several patients with CCOC presented with metastases at time of diagnosis, whereas patients with CCAM usually developed metastases only after several recurrences.

CONCLUSION

Based on the relatively small number of cases in the literature on CCOC and CCAM, it is difficult to confidently separate the 2 lesions. Both lesions should be considered low-grade malignancies and could well represent a clinicopathologic continuum of a single disease entity rather than 2 separate lesions.

Clear cell odontogenic carcinoma: evaluation of reported cases

PURPOSE

We present the cases of 4 patients with clear cell odontogenic carcinoma and a contrasting case of a patient with a calcifying epithelial odontogenic tumor from Massachusetts General Hospital. Differential diagnosis, distinguishing characteristics, and data from 32 cases in the literature are also reported. Because this rare tumor behaves aggressively with both regional and distant spread, a better understanding of its biologic behavior is imperative.

PATIENTS AND METHODS

The 4 patients with clear cell odontogenic carcinoma were women and had an average age of 65 years (range, 40 to 77 years). Three tumors were in the posterior mandible and 1 was in the maxilla. Three patients complained of pain; bony expansion and tooth mobility were noted in isolated cases. A comparison is made with other reported cases, and factors associated with recurrence and survival are presented.

RESULTS

All patients were treated with resection, and 1 patient received postoperative radiotherapy. Two patients with positive surgical margins underwent further resection. All patients have been followed an average of 2 years (range, 0.5 to 4 years) and presently have no evident disease.

CONCLUSIONS

Recognition of this unusual tumor and differentiating it from other clear cell neoplasms is critical in developing an appropriate treatment plan. Management should include wide en bloc resection and long-term follow-up.

Genetic profile of clear cell odontogenic carcinoma

In the head and neck region, clear cell tumors are usually derived from salivary glands, odontogenic tissues, and metastasis. The World Health Organization has classified clear cell odontogenic tumor among benign tumors, but it is now recognized as a more sinister lesion, and current opinion is that it should be designated as a carcinoma. It is characterized by aggressive growth, recurrences, and metastasis. By using complementary DNA microarrays, several genes in clear cell odontogenic tumor were identified that are differentially regulated when compared with non-tumor tissue. In conclusion, the first genetic profiling of clear odontogenic carcinoma is reported. DNA microarrays can potentially help in identifying some genes whose products could be disease-specific targets for cancer therapy as well as a tool for better classifying odontogenic tumor.

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.

Clear cell odontogenic carcinoma

Clear cell tumours, in the head and neck region, are usually derived from salivary or odontogenic tissues, or may be metastatic. A few clear cells may be present in odontogenic cysts, while, odontogenic neoplasms composed predominantly of clear cells are quite rare. They include calcifying epithelial odontogenic tumours (CEOT), ameloblastoma and odontogenic carcinoma. Clear cell odontogenic tumour (CCOT) has been classified in the last WHO classification as a benign tumour, but it is now recognized as a more sinister lesion and current opinion is that CCOT should be designated as a carcinoma. These tumours are characterized by aggressive growth, recurrences, and metastatic disease. A recent review of the literature has yielded 30 cases of tumours with similar characteristics. These tumours have a peak incidence in the 5th-7th decades, with a female predilection. The anterior portions of the jaws, especially the mandible, are most frequently affected. The aggressive potential of these neoplasms is well documented by the extensive invasion of adjacent tissues, multiple recurrences and regional or distant metastases.

Clear cell odontogenic carcinoma: a clinicopathologic and immunocytochemical study of 5 cases

CONTEXT

Odontogenic tumor composed predominantly of clear cells is a rare neoplasm of the jaws that was initially designated as clear cell odontogenic tumor. Subsequent reports in the literature, however, all have indicated that this tumor exhibits an aggressive behavior characterized by infiltrative local growth, recurrence, or metastases.

OBJECTIVE

To ascertain the clinicomorphologic features and biologic behavior of this tumor group, we present 5 additional cases using the term clear cell odontogenic carcinoma.

DESIGN

Histologic and immunohistochemical examinations were performed on clear cell odontogenic carcinomas from 5 patients. Clinical and follow-up data were recorded, and the literature was reviewed.

RESULTS

The patients were 1 man and 4 women with an average age of 42.4 years at diagnosis. Three tumors occurred in the mandible and the other 2 in the maxilla. Four of the 5 cases occurred in the anterior or premolar areas of the jaws, appearing as poorly marginated radiolucencies. All cases consisted of islands and sheets of large clear cells and small basaloid cells with scanty eosinophilic cytoplasm, which were separated by thin, mature, fibrous septae. The tumors were unencapsulated and showed aggressive infiltration of the surrounding muscle and perineural tissues. Most of the clear cells contained cytoplasmic glycogen. Immunocytochemically, the tumor cells were positive for pan-keratin, cytokeratin 19, and epithelial membrane antigen, but were negative for vimentin, S100 protein, desmin, smooth muscle actin, human melanoma antigen (HMB-45), and alpha(1)-antichymotrypsin. Follow-up data showed 4 of 5 patients to have multiple local recurrences, and 1 of these 4 had submandibular lymph node metastasis and a fatal outcome due to uncontrollable tumor growth.

CONCLUSION

These results suggest that odontogenic clear cell neoplasms are at least low-grade malignancies and should be classified as carcinomas.

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 odontogenic carcinoma: A case report and literature review of odontogenic tumors with clear cells

Clear cell odontogenic carcinomas are uncommon epithelial neoplasms that have metastatic potential. We describe such a tumor in a 67-year-old Japanese man with a well-defined, unilocular radiolucent area in the mandible. The tumor was enucleated and has not recurred or metastasized 3 years after surgery. Histologically, the tumor was composed of a predominant clear cell area and a plexiform ameloblastic pattern. The latter was located at the periphery of the tumor. In the English literature, 19 cases of clear cell odontogenic carcinoma, clear cell odontogenic tumor, and clear cell ameloblastoma have been reported. The mean age of the patients at diagnosis was 56.4 years and the gender ratio (M:F) was 8:11. Fourteen tumors were located in the mandible and 5 in the maxilla. Recurrence or metastasis occurred in approximately one half of these patients, and five of the patients died of their disease. More than one half recurrent or metastatic tumors contained palisading clear cells.

Clear cell odontogenic tumour: a case with induction of dentin-like structures?

A case of clear cell odontogenic tumour, which occurred centrally in the mandible of a 56-year-old Japanese woman, is reported with its histochemical, immunohistochemical and ultrastructural findings. Histologically, the tumour nests were composed of large glycogen-rich clear cells and small non-clear polygonal cells and were separated by thin mature fibrous connective tissue septae. Immunohistochemically, both types of tumour cells showed positive expression of various cytokeratins, in particular cytokeratin 19, and of epithelial membrane antigen. Eosinophilic hyaline deposits and possible dentin-like structures were occasionally formed in contact with the epithelial nests and are regarded as indicative of the epithelial-mesenchymal inductive capacity of this tumour. The aggressive nature of the present tumour was assumed through its invasive growth pattern and occasional mitotic figures. Although it was diagnosed as clear cell odontogenic tumour according to the present WHO classification, the patient must be followed carefully because of its probable malignant nature.

Extraosseous calcifying epithelial odontogenic tumor: report of two cases and review of the literature

In this study two additional cases of extraosseous calcifying epithelial odontogenic tumor are reported, both of which exhibited a prominent clear cell component. The clinical and histopathologic findings of these two cases are compared with those of the nine reported cases from the English language literature. The age range for the 11 cases was 12 to 64 years with a mean age of 34.4 years at the time of diagnosis. Six of the tumors involved female patients and five involved male patients. Seven cases were located on the mandibular gingiva with the remaining four cases involving the maxillary gingiva. On microscopic evaluation, six of the lesions exhibited a predominant clear cell component. Appropriate management of the extraosseous calcifying epithelial odontogenic tumor consists of simple excision. No recurrences have been recorded.

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.