A case of clear cell odontogenic carcinoma with an aggressive extension arising in the maxilla

Abstract

We present a rare case of an aggressive clear cell odontogenic carcinoma arising in the maxilla of an 80-year-old female. Grossly, this lesion was a pedunculated tumor. Histologically, the lesion appeared as an atypical epithelium consisting of clear cells and basaloid cells demonstrating papillary and exophytic growth with a narrow fibrovascular stoma. Squamous differentiation was also found in the tumor. Histochemically, diastase-digestible PAS-positive glycogen granules were abundant in the cytoplasm of the clear cells. Immunohistochemically, the basaloid cells were positive for CK5/6 and p63, and were partially weakly positive for CK19. The clear cells were positive for CK19, partially positive for p63, and partially weakly positive for CK5/6. Although the number of p53-positive clear cells and basaloid cells was small, multi-layered Ki-67-positive basaloid cells were observed. A translocation of EWSR1 was detected by fluorescence in situ hybridization. Therefore, this case was diagnosed as a clear cell odontogenic carcinoma. One month after the surgery, multiple metastases of the cancer occurred rapidly in her lymph nodes including her neck and multiple organs including both lungs and liver although no local recurrence was observed. Postoperative chemoradiotherapy was performed, but the disease became uncontrollable, and the patient died five months after the surgery.