An unusual presentation of clear cell odontogenic carcinoma in mandibular anterior region

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.

Detection of EWSR1 fusions in CCOC by targeted RNA-seq

OBJECTIVE

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.

STUDY DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

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.

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.