渡邊 祐作¹, 塩屋 晋吾², 有木園 哲仁¹, 田嶋 修三¹, 帖佐 俊行¹, 杉田 浩¹, 水上 京子¹, 徳留 健太郎¹, 肱黒 薫¹, 重田 浩一朗¹

Yusaku WATANABE¹, Shingo SHIOYA², Tetsuhito ARIKIZONO¹, Syuzou TASHIMA¹, Toshiyuki CHOSA¹, Hiroshi SUGITA¹, Kyouko MIZUKAMI¹, Kentaro TOKUDOME¹, Kaoru HIJIKURO¹, Kouichirou SHIGETA¹

¹霧島市立医師会医療センター消化器内科, ²霧島市立医師会医療センター放射線技術部

¹Department of Gastroenterology, Kirishima Medical Center, ²Department of Radiological Technology, Kirishima Medical Center

キーワード : xanthogranulomatous appendicitis, appendiceal mucocele

症例は20歳代，女性．8年前から潰瘍性大腸炎の既往があり軽度の右下腹部痛を認めたため，定期検査も含めて超音波検査を施行した．虫垂の根部は径3 mmと正常径であったが盲端部に限局した長径25 mm，短径10 mmの腫大を認めた．腫大部の層構造は明瞭で粘膜面の不整や内腔の刷毛状エコー，石灰化は確認できなかった．血流シグナルは捉えられなかった．周囲脂肪織の炎症所見は目立たず腹水や腫大リンパ節は確認できなかった．CT/MRIでも同様の所見であり虫垂粘液嚢腫が疑われ外科手術を施行した．病理所見では組織学的に虫垂粘膜上皮下に泡沫状組織球の集簇とリンパ球浸潤からなる黄色肉芽腫性反応を認め，黄色肉芽腫性虫垂炎と診断された．特異的な所見がないことと，非常に稀な病態のため術前に診断することは困難であるが，腫瘍性病変以外で虫垂にこのような特殊な炎症が起こることがあるということを念頭にいれる必要性があると思われた．

A 20-year-old woman with a history of ulcerative colitis since 2006 presented with mild right lower abdominal pain and underwent ultrasonography for routine examination. The root of the appendix was normal with a diameter of 3 mm, but there was a 9-mm-long swollen appendage localized at the blind end. The laminar structure was clear and there was no irregularity of the mucosal surface, no brush echo, and no calcification of the lumen. No blood flow signal was detected. The isolation sign of the surrounding fatty tissue was not prominent, and ascites and enlarged lymph nodes could not be identified. CT/MRI showed similar findings, and appendiceal mucocele was suspected. Appendectomy was performed. Histologically, a xanthogranulomatous reaction consisting of foamy histiocyte aggregation and lymphocytic infiltration was found under the mucosal epithelium of the appendix, so we diagnosed xanthogranulomatous appendicitis. Although the absence of specific findings and the rarity of this condition precluded a preoperative diagnosis, it is necessary to keep in mind that this particular inflammation can occur in the appendix in addition to neoplastic lesions.