Clear Cell Odontogenic Carcinoma Research Articles

A Comparison of Clear Cell Sarcoma to Jaw and Salivary Tumors Bearing EWS Fusions.

To review tumors identified as "clear cell sarcoma" in order to determine similarities to the rare EWS fusion positive jaw and salivary gland tumors clear cell odontogenic carcinoma (CCOC) and clear cell carcinoma of the salivary gland (CCC). PubMed was used to collect all reports of clear cell sarcoma (CCS). Search parameters were "clear cell sarcoma" and "CCS." References in the publications were screened and cross-referenced. Data extracted included demographic characteristics, presenting signs and symptoms, radiographic findings, histological and immunohistochemical features and known molecular/genetic aberrations. Clear cell sarcoma has several similarities to CCOC and CCC. All three tumor types have similar histologic appearances including the presence of clear cells, as well as similar genetic profiles in that all harbor an EWSR1-CREB family fusions. Additionally, these tumors appear in soft tissue as well as bone, and can have a prolonged clinical course. CCS can appear anywhere in the body, including the head and neck region. All three tumors appear to have a predilection to women, although CCS may have a slight younger age of onset as compared to CCOC and CCC (3rd vs 5th decade of life, respectively). Gaining a better understanding of the similarities and differences between these three tumors may lead to a better understanding of each one.

Abstract 3657: Customized liquid biopsy assay for monitoring EWSR1 fusions in sarcomas

Abstract Background: Gene fusions involving EWSR1 are involved in certain rare sarcomas and sarcoma-like tumors such as, for example, Ewing sarcoma, clear cell sarcoma, hyalinizing clear cell carcinoma, and clear cell odontogenic carcinoma. EWSR1-FLI1 fusions are found in Ewing sarcoma, while EWSR1-ATF1 and EWSR1-CREB are characteristic of clear cell sarcoma among others. Liquid biopsies involve obtaining tumor-derived materials through minimally invasive methods such as blood or other body fluid collection. Analysis of cell-free DNA (cfDNA) is an attractive method to identify gene fusions and monitor tumor recurrence and minimal residual disease (MRD). However, the structural complexity of oncogenic rearrangements poses challenges for the detection using plasma assays. We present a novel assay to monitor fusion positive tumor DNA in a busy oncology clinic. Methods and Patients: Patients with EWSR1 fusion positive sarcomas are identified through clinical RNA-based sequencing. Tumor DNA isolated from biopsy or surgical samples is sequenced to map the intronic breakpoint and customized primers spanning the breakpoint are designed for each patient. The breakpoint is subsequently confirmed through PCR. The product length of ~100bp accounts for the small shedding size of tumor cfDNA. A quantitative TaqMan assay is designed to confirm EWSR1 fusions. The limit of detection is determined by a dilution series of tumor DNA. cfDNA is extracted from blood samples of the patients at multiple timepoints, the tumor burden is quantified by TaqMan Assay and subsequently correlated with clinical findings from imaging studies such as tumor progression or remission. Results: We consented 10 patients with EWSR1 fusion positive tumors to participate in this study. Plasma samples were collected for 8, resulting in 26 total timepoints. Breakpoints were identified in 9 patients and confirmed with PCR on original tumor DNA. TaqMan assays were designed for 5 patients and showed correlation between the tumor burden detected in EWSR1-ATF1 copies in cfDNA extracted from patient blood and the therapeutic response to treatment found through imaging studies. One patient was followed over the period of 9 months, and a total of 5 plasma timepoints were collected. The patient started with a low number of EWSR1-ATF1 copies of <1ng/ul, while on a Iurbinectedin/irinotecan therapy and showed a mixed response in the CT scan. After withdrawing from that therapy and starting other therapy regimens, the EWSR1-ATF1 copies increase to 8ng/ul, correlating with tumor progression observed in CT scans. Conclusion: Our results suggest that ESWR1 fusions in sarcomas can serve as biomarkers to measure tumor burden. Our approach using an individually tailored cfDNA TaqMan assay could provide a valuable monitoring tool to inform clinicians about tumor progression or MRD. With these proof-of-principle findings we can now determine clinical validity and utility. Citation Format: Annie Li, Julia C. Thierauf, Bianca Gonda, Rashi Purohit, Stefan T. Kaluziak, Elizabeth Codd, Stacey N. Dybel, Edwin Choy, Gregory M. Cote, Jochen K. Lennerz, A John Iafrate. Customized liquid biopsy assay for monitoring EWSR1 fusions in sarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3657.

Clear Cell Odontogenic Carcinoma: Diagnostic Approach to Exclude the Unclear

Clear Cell Odontogenic Carcinoma: Diagnostic Approach to Exclude the Unclear

Frequency of central odontogenic tumors: a retrospective study in an Iraqi population utilizing 2022 WHO head and neck tumors classification

Objectives: Odontogenic tumors occupy an important position among head and neck tumors. Although, rarely encountered in medical practice but they considered increasingly challenging lesions for the clinicians due to their overlapping clinical and histopathological features. This study was designed to determine the relative frequency of central odontogenic tumors in an Iraqi population by utilizing 2022 WHO tumor classification. Material and Methods: Sixty cases of central odontogenic tumors from a total of 1869 case records were retrieved retrospectively from the file archive of the histopathology laboratory in Baghdad medical city from the period of 2016 to 2021. For each individual case, data regarding age, gender, location, and tumor type were collected and analyzed. Results: odontogenic tumors constituted 3.2% of the total cases analyzed mostly benign. The male to female ratio was 1/1. The age of the patients ranged from 11 to 75 years. Most cases were recorded in the third and fourth decades of life (n=31, 51.6%). The most common benign and malignant tumors were ameloblastoma and ameloblastic fibrosarcoma respectively. Most of these tumors located in the mandible (n= 45, 75%). The most common mandibular tumor was ameloblastoma followed by ameloblastic fibroma, and odontogenic myxoma. Regarding maxillary tumors, the predominant tumor was ameloblastoma followed by ameloblastic fibroma, ameloblastic fibrosarcoma, and clear cell odontogenic carcinoma. Conclusions: Odontogenic tumors in an Iraqi population occurred more commonly in the mandible and showed no sex predilection. Most cases were diagnosed in third and fourth decades of life and ameloblastoma was the most frequent odontogenic tumor. The relative frequency of malignant odontogenic tumors was 11.67% of all cases studied mostly ameloblastic fibrosarcoma. KEYWORDS Odontogenic tumors, WHO tumor classification, Frequency, Ameloblastoma.

Clear cell Odontogenic Carcinoma Mandible Mimicking oral Cavity Squamous cell Carcinoma: An Intriguing case with Review of Literature.

Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic neoplasm with high risk of recurrence and aggressive behaviour. Presence of clear cells in head and neck is hallmark, but not pathognomic for the entity. Deceptive behaviour admist wide range of differentials, poses an immense diagnostic challenge. An incisional biopsy with appropriate immunohistochemistry is prudent for diagnosis. We herein report atypical case of CCOC mimicking squamous cell carcinoma, in a tertiary cancer center in North Eastern part of India.

Homeobox Genes in Odontogenic Lesions: A Scoping Review.

Homeobox genes play crucial roles in tooth morphogenesis and development and thus mutations in homeobox genes cause developmental disorders such as odontogenic lesions. The aim of this scoping review is to identify and compile available data from the literatures on the topic of homeobox gene expression in odontogenic lesions. An electronic search to collate all the information on studies on homeobox gene expression in odontogenic lesions was carried out in four databases (PubMed, EBSCO host, Web of Science and Cochrane Library) with selected keywords. All papers which reported expression of homeobox genes in odontogenic lesions were considered. A total of eleven (11) papers describing expression of homeobox genes in odontogenic lesions were identified. Methods of studies included next generation sequencing, microarray analysis, RT-PCR, Western blotting, in situ hybridization, and immunohistochemistry. The homeobox reported in odontogenic lesions includes LHX8 and DLX3 in odontoma; PITX2, MSX1, MSX2, DLX, DLX2, DLX3, DLX4, DLX5, DLX6, ISL1, OCT4 and HOX C in ameloblastoma; OCT4 in adenomatoid odontogenic tumour; PITX2 and MSX2 in primordial odontogenic tumour; PAX9 and BARX1 in odontogenic keratocyst; PITX2, ZEB1 and MEIS2 in ameloblastic carcinoma while there is absence of DLX2, DLX3 and MSX2 in clear cell odontogenic carcinoma. This paper summarized and reviews the possible link between homeobox gene expression in odontogenic lesions. Based on the current available data, there are insufficient evidence to support any definite role of homeobox gene in odontogenic lesions.

Clear Cell Odontogenic Carcinoma of the Mandible, Case Report

Caucasian patient, ECOG-PS 0, 38 years old, presented at the hospital with symptoms of pain in the lower left region of the mandible, objectively without swelling, on radiographic examination, she presented an extensive lesion with radiolucency in the region of element 37, with image filling, displacement of element 38 and apical involvement of element 36. In the tomographic exam, he presented a lesion with great destruction of the lingual wall and accentuated bone sequestration. It was opted for the differential diagnosis of the same by biopsy of the region with partial removal of healthy and diseased tissue associated with aspiration puncture, the histopathological examination was diagnosed as odontogenic clear cell carcinoma, a rare malignant tumor of epithelial origin, common in aged over 50 years and without behavioral pattern at its emergence.

UNUSUAL PRESENTATION OF MALIGNANT LESION OF CLEAR CELLS: A DIAGNOSTIC CHALLENGE

Clear cell odontogenic carcinoma (CCOC) and hyalinizing clear cell carcinoma (HCCC) are rare malignancies that arise from different histologic origin. The histology is similar, and in some cases it is impossible to distinguish both lesions. We report an unusual presentation of well-defined nodular lesion affecting the maxillary gingival in a 19-year-old female patient presenting clinically as a benign or reactive-like lesion. Periapical radiography showed a discrete area of resorption of the alveolar bone. The patient was submitted to an excisional biopsy. The material was sent for histopathologic and immunohistochemical examination. The diagnosis was carcinoma with a clear cell pattern, and it is not possible to distinguish between CCOC and HCCC. In this study, clinicopathologic, histologic, and immunohistochemical features of CCOC and HCCC were discussed because the histologic diagnostic was challenging. Radical surgical treatment and rehabilitation were performed. The patient is under follow-up without signs of recurrence.

Detection of EWSR1 fusions in CCOC by targeted RNA-seq

To describe the application of a targeted RNA sequencing assay to detect fusion transcripts in formalin-fixed paraffin-embedded (FFPE), non-decalcified samples of clear cell odontogenic carcinoma (CCOC) and related tumors, and to add to knowledge of the genetic drivers of CCOC. Five FFPE tissues, including intraosseous CCOC (n=3), clear cell carcinoma of the salivary gland (CCC, n=1), and Ewing sarcoma (ES, n=1), were analyzed by targeted RNA-seq to detect fusions. The 3 intraosseous CCOC samples harbored EWSR1 translocations: EWSR1-ATF1 (n=2) and EWSR1-CREM (n=1); the CCC sample contained an EWSR1-ATF1 fusion; and the ES sample contained an EWSR1-FLI1 fusion detected by RNA-seq. These results demonstrate that targeted RNA-seq is a valuable tool to detect fusions in FFPE samples of rare tumors such as CCOC and CCC. The results also confirm the observations that CCOC is driven by fusions between EWSR1 and CREB family transcription factors, including ATF1 and CREM. To our knowledge, this is the second report of CCOC with an EWSR1-CREM translocation.

Biphasic clear cell odontogenic carcinoma: An aggressive metastatic neoplasm

AbstractIntroductionThe recent classification of odontogenic tumours includes the entities clear cell odontogenic carcinoma (CCOC) and clear cell ameloblastoma (CCAM) under the unifying name CCOC. The lack of ameloblastic differentiation in many cases of CCOC, its more aggressive behaviour and unique molecular profile suggest a distinct entity which merits its own standing in the classification of odontogenic carcinomas.Case reportA 53‐year‐old male presented with excessive hyperplastic tissue in the anterior maxilla. Microscopic examination disclosed a biphasic clear cell neoplasm with nests of polygonal clear cells, surrounded by intensely eosinophilic flattened cells. The tumour cells were immunoreactive for MNF 116, CK 14, CK 19, CK 5 and EMA. The proliferation index, Ki67, was low and its expression, similar to the basal‐cell‐specific cytokeratins (CK 14 and CK5), was confined to the peripheral cells. Molecular studies confirmed EWSR1 gene rearrangements. An anterior maxillectomy was performed, supplemented with radiotherapy. Three years after resection, multiple metastatic bodies were detected in the lung and the patient passed away 1 year later.ConclusionThis case further supports the notion that CCOC with biphasic histomorphology appears to have a high mortality rate, and it may be wise to treat and monitor these patients more aggressively.

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 89years, for females 56.4 and males 53.6years. The mean size was 3.41cm. 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 30.3months, 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.

Sequential treatment from mandibulectomy to reconstruction on mandibular oral cancer - Case review II: mandibular anterior and the floor of the mouth lesion of basaloid squamous cell carcinoma and clear cell odontogenic carcinoma

Preoperative patient analysis for oral cancer involves multiple considerations that are based on multiple factors; these include TNM stages, histopathologic findings, and adjacent anatomical structures. Once the decision is made to excise the lesion, the margin of dissection and its extent should be considered along with the best form of reconstruction and airway management. Treatment methods include surgical resection, radiotherapy, and chemotherapy. Although the combined method of treatment is controversial, surgical resection is considered predominantly, and immediate reconstruction after surgical resection follows. The choice of treatment is dictated by the anticipated functional and esthetic results of treatment and also by the availability of a surgeon with the required expertise. Segmental mandibulectomy with primary reconstruction has been shown to have advantages in both functional and esthetic results. A 52-year-old male patient with basaloid squamous cell carcinoma of the floor of the mouth, and the anterior portion of the mandible was treated with surgical procedures that included segmental mandibulectomy with both supraomohyoid neck dissection (SOHND) at Levels I–III and mandible reconstruction with a left fibula free flap. A 55-year-old male patient with clear cell odontogenic carcinoma of the oral cavity underwent segmental mandibulectomy with both SOHND at Levels I–III and mandible reconstruction with a left fibula free flap. The purpose of this study was to review the anatomic and functional results of patients after immediate reconstruction with a fibula free flap following resection of carcinoma in the anterior portion of the mandible and floor of the mouth.

CLEAR CELL ODONTOGENIC CARCINOMA: REPORT OF 3 NEW CASES AND SUMMARY OF 124 REPORTED CASES

<h3>Background</h3> Clear cell odontogenic carcinoma (CCOC) is a rare and hard-to-diagnose tumor first described by Hansen et al. in 1985. CCOC is associated with aggressive clinical behavior, metastasis, low survival rate, and difficulty in diagnosis. <h3>Objective</h3> In this study we present clinicopathologic and immunohistochemical features of 3 new cases of CCOC and summarize the features of currently published cases in order to enhance the diagnosis. <h3>Methods</h3> A search was performed with keywords "CCOC" and "clear cell odontogenic carcinoma" using the PubMed, Scopus, and Science Direct databases from 1985 to 2019. <h3>Results</h3> A total of 124 cases of CCOC were reported in literature through the end of 2019. CCOC is frequently seen in the fifth decade, with a mean age of 55.2 years. It occurs in the mandible 3 times more often than in the maxilla and has significant female predilection (61.3%). We analyzed 3 new cases, 2 female patients and 1 male patient, with a mean age of 56.6 years. Immunohistochemical analysis revealed positive immunoreactivity to EMA, CK7, CK14, CKAE1/AE3, P63, and HMW-CK and negative result for CD10, vimentin, and S100. <h3>Conclusions</h3> Considering reported cases we cannot say that CCOC is rare but we are still facing a great challenge in diagnosis of this tumor owing to its microscopic similarity to other clear cell tumors. Further immunohistochemical or gene expression analyses are needed to distinguish CCOC from other oral cancers.

Clinico-pathological study of malignant odontogenic tumours from a national referral centre

BackgroundMalignant odontogenic tumours are extremely rare tumours occurring within the jaws. Our study was performed to determine the demographic and clinico-pathological features of malignant odontogenic tumours amongst a multi-ethnic Asian population.MethodsThis was a retrospective cross-sectional study of malignant odontogenic tumours diagnosed at the Institute for Medical Research, Malaysia, from 2009 to 2019. All cases were independently reviewed and reclassified following the criteria set out in the latest edition of the World Health Organization 2017 reference text. Demographic and clinico-pathological data were recorded for each case.ResultsTwenty-four cases of malignant odontogenic tumours were identified. The patients’ age ranged from 16 to 79 years with the mean age at diagnosis being 50.8 years (SD = 16.18). There was a male predominance (66.7%) in this cohort of patients. The ethnic distribution appeared to reflect the Malaysian population with most cases seen amongst the Malay ethnic group (66.7%). Ameloblastic carcinoma was the most frequently diagnosed malignant odontogenic tumour (45.8%) and was also predominantly seen in males (90.9%). All patients with clear cell odontogenic carcinoma were females. There was no obvious sex predilection in primary odontogenic carcinoma not otherwise specified (NOS). The mandible (79.2%) was more frequently involved compared to the maxilla.ConclusionsDiagnosis and management of malignant odontogenic tumours are challenging due to the rarity of these tumours. Our study has elucidated the clinico-pathological features of malignant odontogenic tumours seen in a multi-ethnic Asian population.

A case of clear cell odontogenic carcinoma of the mandible diagnosed by identification of the &lt;i&gt;EWSR1-ATF1&lt;/i&gt; fusion gene

A case of clear cell odontogenic carcinoma of the mandible diagnosed by identification of the &lt;i&gt;EWSR1-ATF1&lt;/i&gt; fusion gene

CLEAR CELL ODONTOGENIC CARCINOMA IN POSTERIOR REGION OF MANDIBLE: A CASE REPORT

Clear cell odontogenic carcinoma (CCOC) is a rare intraosseous carcinoma, potentially aggressive, capable of frequent recurrences loco-regional and metastasis. Here, we describe a 28-year-old female patient presenting a swelling in the region of the teeth 43 to 45. Radiographically, was observed hypodense associated with hyperdense areas causing buccal and lingual expansion. In the microscopic analysis, it was reported odontogenic neoplasia characterized by islands and cords of epithelial cells with peripheral composed by cuboidal/cubic cells, arranged in palisade, with inverted polarity, sometimes vacuolized, and centrally composed of polygonal and basaloid cells, some of them, with clear cytoplasm. The neoplasia presented no capsule and produced peripheral bone resorption and perivascular invasion. The periodic acid–Schiff reaction showed glycogen positive and immunohistochemical analysis revealed intense positivity for CK14, consistent with clear cell odontogenic carcinoma. The patient was submitted to resection surgery, where the same histologic pattern was observed, and is under clinical-radiographic follow-up. Clear cell odontogenic carcinoma (CCOC) is a rare intraosseous carcinoma, potentially aggressive, capable of frequent recurrences loco-regional and metastasis. Here, we describe a 28-year-old female patient presenting a swelling in the region of the teeth 43 to 45. Radiographically, was observed hypodense associated with hyperdense areas causing buccal and lingual expansion. In the microscopic analysis, it was reported odontogenic neoplasia characterized by islands and cords of epithelial cells with peripheral composed by cuboidal/cubic cells, arranged in palisade, with inverted polarity, sometimes vacuolized, and centrally composed of polygonal and basaloid cells, some of them, with clear cytoplasm. The neoplasia presented no capsule and produced peripheral bone resorption and perivascular invasion. The periodic acid–Schiff reaction showed glycogen positive and immunohistochemical analysis revealed intense positivity for CK14, consistent with clear cell odontogenic carcinoma. The patient was submitted to resection surgery, where the same histologic pattern was observed, and is under clinical-radiographic follow-up.

CLEAR CELL ODONTOGENIC CARCINOMA: A RARE CASE REPORT

Clear cell odontogenic carcinoma (CCOC) is a rare malignant neoplastic process originating from the odontogenic epithelium presenting high aggressive potential. The patient, a 45-year-old male, was referred to an oral and maxillofacial surgery and traumatology referral service, reporting painful symptoms after a local anterior mandible region fracture. A histopathologic examination revealed epithelial neoplasia fragments characterized by cell proliferation in islands, cords, nests, and, occasionally, cystic spaces. The proliferating cells were pleomorphic, with a markedly clear cytoplasm. An immunohistochemical analysis was then performed, and a strong immunohistochemical reaction to CK14 and CK19 antibodies was detected for the neoplastic epithelial cells. Immunostaining was consistent with a neoplastic process of odontogenic origin. The established diagnosis was, thus, determined as CCOC. The patient was then referred to a cancer treatment reference service to undergo surgical treatment. The patient is currently in regular follow-up, without any clinical-radiographic signs of recurrence. Clear cell odontogenic carcinoma (CCOC) is a rare malignant neoplastic process originating from the odontogenic epithelium presenting high aggressive potential. The patient, a 45-year-old male, was referred to an oral and maxillofacial surgery and traumatology referral service, reporting painful symptoms after a local anterior mandible region fracture. A histopathologic examination revealed epithelial neoplasia fragments characterized by cell proliferation in islands, cords, nests, and, occasionally, cystic spaces. The proliferating cells were pleomorphic, with a markedly clear cytoplasm. An immunohistochemical analysis was then performed, and a strong immunohistochemical reaction to CK14 and CK19 antibodies was detected for the neoplastic epithelial cells. Immunostaining was consistent with a neoplastic process of odontogenic origin. The established diagnosis was, thus, determined as CCOC. The patient was then referred to a cancer treatment reference service to undergo surgical treatment. The patient is currently in regular follow-up, without any clinical-radiographic signs of recurrence.

CLEAR CELL ODONTOGENIC CARCINOMA: A CASE REPORT

A 50-year-old woman with a previous diagnosis of ameloblastoma was referred to the School of Dentistry Brazil complaining of a symptomatic lesion in the body and ramus mandibular. Her medical history was unremarkable. The intraoral examination demonstrated an exophytic tumor mass in the right posterior alveolar ridge. Computed tomography revealed a lesion with irregular margins extending from first premolar to distal to second molar of the left side of the mandible. A provisional diagnosis of recurrent ameloblastoma was considered, and an incisional biopsy was performed. Histopathologic evaluation of the specimen showed nests, follicles, and cords of epithelial clear cells. In occasional follicles the central cells showed a reticulum-like pattern, and some central cells showed keratinization. Peripheral cells presented palisading and reverse nuclear polarity. Necrosis, cellular, and nuclear pleomorphism were also observed. Final diagnosis of clear cell odontogenic carcinoma was established. The patient was referred for treatment and is being followed up.

Clear cell odontogenic carcinoma an enigmatic diagnostic challenge

Clear cell odontogenic carcinoma (CCOC) is an extremely rare odontogenic carcinoma with few cases reported in literature. In 2005, the WHO reclassified CCOC as a malignant odontogenic neoplasm, exhibiting an aggressive growth pattern with a propensity for regional, nodal, and distant metastasis. Being characterized histopathologically by sheets and islands of clear and vacuolated cells, it poses a diagnostic challenge to the clinician and pathologist to distinguish CCOC from other perplexing clear cell entities and requires immunohistochemical analysis. Here, we report a case of CCOC in a 50-year-old woman who presented with a solitary, diffuse, and tender swelling in the posterior aspect of the mandible for 1½ months. Wide local excision was performed for the case. The present case may aid to delineate its biological behavior along with shedding light on its histopathological and immunohistochemical character, thus contributing to the literature.

Clear cell odontogenic carcinoma with skeletal metastasis: A rare case report

Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic malignancy with a female preponderance occurring in the adult age group. CCOC was classified as a malignant neoplasm of odontogenic origin by the World Health Organization in 2005 because of its aggressive nature, local recurrence tendency, and the potential for regional and distant metastasis. Histologically, CCOC is characterized by sheets and islands of vacuolated and clear cells. Metastasis at presentation is rare; it usually involves cervical lymph nodes and lungs, less frequently to bone. As clear cells are present in few odontogenic tumors; salivary gland neoplasms; and metastatic tumors to the jaws, especially metastatic renal cell carcinoma, the presence of clear cells in a lesion of the head and neck region poses a diagnostic challenge. So knowledge about the clinical course, histopathological pattern, and immunoprofile of CCOC helps in differentiating the other clear cell tumors.