副鼻腔・頭蓋底原発clear cell carcinomaの1例

Primary Clear Cell Carcinoma of the Skull Base and Paranasal Cavity: A Case Report

Ⅰ．はじめに

　画像診断の進歩に伴い，腫瘍性病変の術前診断はより正確に実施可能となってきた．しかし，年齢，局在などからある程度の鑑別は可能であるが，稀な疾患ほど非侵襲的なcomputed tomography（CT）やmagnetic resonance imaging（MRI）などでの診断に苦慮することも多い．Clear cell carcinoma（CCC）は，腎，唾液腺，肺，副甲状腺，甲状腺，女性器など各腺組織に発生する，ジアスターゼで消化されるperiodic acid-Schiff（PAS）染色陽性のグリコーゲンを含む半透明の細胞質をもつ腫瘍であるが，副鼻腔原発のCCCは過去に3例の報告をみるのみである．

　今回，画像診断に苦慮した副鼻腔原発のCCCを経験したので，その臨床経過，診断，治療に関して報告する．

　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 (¹⁸fluorodeoxy 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.