図７〜図１０に2cmを超える巨大結石（１）が，図１２に小結石（２）がある．どこまでが盲腸か判断困難だが，手術所見によると結石（１）は虫垂根部に嵌頓しているので図７〜図１３の▲が虫垂である．虫垂は腫大し，周囲脂肪組織の濃度上昇と腹膜の肥厚を認め（△）急性虫垂炎の所見である．上行結腸（A）は図１まで粘膜下浮腫による壁肥厚を示し，虫垂根部の炎症の強さを反映しているものと思われる．図５で憩室を認めるので（↑）図４〜図６の結石（白矢印）は憩室内の糞石であろう．手術で27mm大に腫大した虫垂（図A：粘膜面）と虫垂根部に嵌頓した20mm大の結石（１）と小結石（２）を認めた．病理： Chronic appendicitis（下記文献参照）．

文献考察：慢性虫垂炎のCT所見は急性虫垂炎と同様である．
１）Am J Emerg Med. 1998 Jan;16(1):26-33.
The computed tomography appearance of recurrent and chronic appendicitis.
Rao PM, Rhea JT, Novelline RA, McCabe CJ.

The objective of this study was to determine computed tomography (CT) appearance of recurrent and chronic appendicitis. In 100 consecutive appendiceal CT examinations of proven appendicitis, 18 patients met criteria for recurrent (multiple discrete episodes) or chronic (continuous symptoms > 3 weeks, pathological findings) appendicitis. CT findings were reviewed. Ten patients had recurrent appendicitis, 3 had chronic appendicitis, 3 had both, and 2 had pathological chronic appendicitis. CT findings in 18 recurrent/chronic cases were identical to 82 acute appendicitis cases, including pericecal stranding (both 100%), dilated (> 6 mm) appendix (88.9% versus 93.9%), apical thickening (66.7% versus 69.5%), adenopathy (66.7% versus 61.0%), appendolith(s) (50% versus 42.7%), arrowhead (27.8% versus 22.0%), abscess (11.1% versus 11.0%), phlegmon (11.1% versus 6.1%), and fluid (5.6% versus 19.5%). CT findings in recurrent and chronic appendicitis are the same as those in acute appendicitis. Appendiceal CT can be beneficial for evaluating patients with suspected recurrent or chronic appendicitis.PMID: 9451309

２）AJR Am J Roentgenol. 2002 Sep;179(3):731-4.
Chronic inflammatory appendiceal conditions that mimic acute appendicitis on helical CT.
Checkoff JL, Wechsler RJ, Nazarian LN.

OBJECTIVE: Acute appendicitis is commonly diagnosed on CT, but chronic appendiceal processes can mimic acute appendicitis. The purpose of this study was to identify the frequency of these alternative conditions and their findings on helical CT. CONCLUSION: Chronic inflammatory conditions other than acute appendicitis were found in 9% of patients who underwent surgery after CT findings were interpreted as suspicious for appendicitis. These inflammatory conditions were indistinguishable from acute appendicitis when we used either primary or secondary CT signs.PMID: 12185054