[Primary clear cell carcinoma of the skull base and paranasal cavity: a case report].

We described a case of primary clear cell carcinoma (CCC) of the paranasal cavity and skull base. A 59-year-old female experienced chronic nasal obstruction and double vision. Computed tomography (CT) scan revealed a mass lesion of the paranasal cavity, reaching the skull base and intracranial zone. We performed a biopsy by endonasal endoscopic surgery and pathological examinations revealed the tumor was a clear cell carcinoma. No primary tumor was identified on evaluation of the whole body by CT scan and FDG-PET (18 fluorodeoxy glucose positron emission tomography) scan, so we diagnosed a primary CCC of the paranasal cavity. We decided to use stereotactic radiation therapy. Neurologically, her diplopia was improved. The patient is well at 2 years of follow-up with no evidence of local enlargement. There are some reports about the metastatic sinonasal CCC, but there are few reports about primary nasal and sinonasal CCC. This is the fourth case report of primary nasal and sinonasal CCC.