食道黄色腫の2例

Esophageal Xanthoma, Report of Two Cases

要旨　食道黄色腫（xanthoma）は極めてまれとされているが，筆者の経験では，内視鏡検査施行例中0.46％の頻度であった．食道xanthomaの典型例は，非常に微小な黄白色斑が多数集簇する，黄白色の領域として観察される．病理学的には，多数の泡沫細胞（foam cells）が線維化や慢性炎症を伴って粘膜固有層の上皮下乳頭内に充満し，乳頭の拡張が認められる．大きさは1～6mmほどと小さいものが多い．拡大観察すると，乳頭の配列に沿って集合する円形から不整形の微細な黄白色斑の集簇として観察され，表面には縮れた微細血管が観察される．圧倒的に男性に多く，食道癌や頭頸部癌を合併した症例がほとんどであった．病因は明らかになっていないが，様々な食道への刺激（飲酒や喫煙，放射線治療など）が要因となっていることが示唆された．

　Esophageal xanthoma is extremely rare. On the basis of our experience, we estimate that xanthoma is found in 0.46％of patients undergoing endoscopy. Classic cases of esophageal xanthoma were characterized by yellowish white regions consisting of many aggregates of very fine, yellowish white patches. Histopathologically, the subepithelial papillae of the proper mucosae were filled with many xanthoma cells (foam cells), associated with fibrosis and chronic inflammation, and the papillae were dilated. Lesions were only 1 to 6 mm in diameter. Magnifying endoscopy revealed aggregates of round or irregularly shaped, fine, yellowish white patches along the papillae. Tortuous microvessels were observed on the surface. Patients with esophageal xanthoma were overwhelmingly male. Most patients had esophageal cancer or head and neck cancer. The causes of esophageal xanthoma remain unclear. However, various stimuli that irritate the esophagus (e. g., alcohol drinking, smoking, and radiotherapy) were suspected to cause this disease.