Clear cell odontogenic carcinoma (CCOC), a very rare neoplasm located mostly in the mandible, has been regarded as a benign tumor. However, due to the accumulation of case reports, CCOC has been reclassified as a malignant entity by the World Health Organization. Patients with CCOC present with regional swelling and periodontal indications with variable pain, often remaining misdiagnosed for a long period. CCOC has slow growth but aggressive behavior, requiring radical resection. Histologic analysis revealed the monophasic, biphasic, and ameloblastic types of CCOC with clear cells and a mixed combination of polygonal and palisading cells. At the molecular level, CCOC shows the expression of cytokeratin and epithelial membrane antigen, along with markers that assign CCOC to the sarcoma family. At the genetic level, Ewing sarcoma breakpoint region 1-activating transcription factor 1 fusion is regarded as the key feature for identification. Nevertheless, the scarcity of cases and dependence on histological data delay the development of an efficient therapy. Regarding the high recurrence rate and the potential of distant metastasis, further characterization of CCOC is necessary for an early and accurate diagnosis.

Clear cell odontogenic carcinoma (CCOC) is an extremely rare odontogenic neoplasm; Only a few cases have been reported in the English literatures. It displays a propensity for the mandible, most commonly presenting in the fifth to seventh decades, with a female predilection. The clinical and radiological manifestations are multiple and the diagnosis is histological. Histological feature is of large islands and strands of uniform cells with round or ovoid nuclei and clear cytoplasm. Clinically, painless swelling is the most common symptom, followed by pain, teeth mobility, and paresthesia. CCOC has a good prognosis after surgery. This case report presents the histopathological and clinical features of CCOC excised from the mandible.

Clear cell odontogenic carcinoma (CCOC) is a very rare malignant neoplasm of jaw, with a significant clear cell component. It is nearly three times as common in the mandible with distinct female predominance. Past, identified as locally invasive tumor, CCOC is now considered to be malignant neoplasm, showing distant and regional lymph node metastasis. CCOC is histopathologically characterized by large glycogen-rich clear cells, often intermixed with eosinophilic cells. When diagnosing CCOC, ruling out salivary gland tumors, such as mucoepidermoid carcinoma or clear cell adenocarcinoma is important because they have overlapping histologic features with CCOC. Here in, we report a case of CCOC involving the right maxillary sinus of a 72-year-old female.