盲腸（C）は図６で盲端になり，回腸末端（ＴＩ）は図１から始まり下行する．図５の1〜図８の4が虫垂で．周囲脂肪組織の炎症所見はないが，壁は造影効果を受け，2ｃｍ大に腫大し，急性虫垂炎である．図Aが切除標本で，病理診断：phlegmonous appendicitis．

参考症例（先端に限局した急性虫垂炎）：15歳男児．2日前に下腹部痛が出現し，前日から次第に増強してきた．当日に発熱が加わり来院した．体温：38.2℃，下腹部正中に圧痛，反跳痛と筋性防御がある．

麻痺性イレウスを示唆するように右側結腸と小腸が液状内容物とガスで拡張しており，虫垂炎なら穿孔または壊死性虫垂炎を推測する．図５と図６で結石（↑）を認め，図６の1と図７の２は短いが腫大した虫垂と解釈すべきである．図５の結石（糞石・虫垂石）と盲腸との連続性は確認できない．5mmスライスCTで正常虫垂を認識できるのは75％といわれる（下記文献）ので，distal appendicitisの25％は盲腸との連続性を証明できないことになる．図Aで先端だけの虫垂炎を示しており，穿孔性虫垂炎であった．

文献考察：先端に限局した虫垂炎はfalse-negativeになりやすい．
Radiology. 1996 Sep;200(3):799-801.
Focal appendicitis confined to the tip: diagnosis at US.
Lim HK, Lee WJ, Lee SJ, Namgung S, Lim JH.

PURPOSE: To evaluate the diagnostic value of graded-compression ultrasonography (US) for the diagnosis of focal appendicitis confined to the tip. MATERIALS AND METHODS: During a 4-year period, US was performed in 1,450 patients with clinically suspected acute appendicitis. Of these patients, 443 had appendicitis at pathologic examination, 20 of whom had focal appendicitis confined to the tip. Focal appendicitis confined to the tip was defined as occurring when the resected specimen had inflammation only at the distal third of the appendix. RESULTS: Of 20 patients with focal appendicitis confirmed at pathologic examination, 17 patients (85%) had focal appendicitis that was correctly diagnosed at US. The remaining three patients' appendices were diagnosed at US as normal (false-negative cases). Five patients had perforation at the tip, and one patient had an appendicolith. CONCLUSION: Although US appears to be fairly accurate in the diagnosis of focal appendicitis confined to the tip, the entire length of the appendix should be evaluated in order to avoid a false-negative diagnosis.PMID: 8756934