虫垂腫瘤診断における画像診断の役割

The Role of Imaging Techniques in Diagnosing Appendiceal Mass

要旨　術前検査が施行され組織学的に検索された虫垂の腫瘤形成性疾患16例を対象に，各種画像診断法の有用性について検討した．虫垂切除歴のない全例において注腸X線検査（BE）では虫垂は造影されず，大腸内視鏡検査（CF）で虫垂開口部は確認できなかった．結腸型虫垂癌2例はBEとCFで悪性所見が認められ，うち1例は生検でGroup Vであった．粘液瘤7例はBEとCFで粘膜下腫瘍に極めて類似した像を呈し，盲腸内腔への突出が目立つ3例では“はち巻きひだ”が認められた．これに対して，CTと超音波検査（echo）は粘液瘤診断に極めて有効であり，境界明瞭な薄壁で囲まれた囊胞像を呈し，更にBEとCFでは指摘困難な腹膜偽粘液腫の合併を描出できた．虫垂周囲膿瘍はBEとCFでは盲腸の変形や圧排所見が認められ，CTでは石灰化や索状影がみられたが，1つの検査法による虫垂周囲膿瘍の診断は困難であった．翻転虫垂切除断端では病歴の確認が重要である．

　Study was undertaken regarding the usefulness of a variety of imaging methodologies used in diagnosing 16 cases of an appendiceal mass in which histological examination was done preoperatively. In all cases in which appendectomy had not been done before, barium enema (BE) did not visualize appendix and colonofiberscopic examination (CF) was not useful in identifying the appendiceal orifice.

　Findings of malignancy were obtained by BE and CF in 2 caces of colon type appendiceal cancer, one of which case revealed Group V by biopsy. Seven cases of appendiceal mucocele exhibited the pattern highly resembling submucosal tumor and 3 of these with conspicuous protrusion into the cecal lumen had “headband fold”. On the other hand, CT scan and ultrasonographic examination (echo) were extremely useful in describing cystic pattern clearly demarcated by thin wall. Furthermore they detected a complication of pseudomyxoma peritonei, the presence of which was not suggested by BE and CF. Periappendiceal abscess presented with deformity and compression of the cecum by BE and CF, and with calcification and radiated spicular shadow by CT. Definitive diagnosis of periappendiceal abscess, however, was not possible by a single imaging technique. A retracted stump of the resected appendix mandates the confirmation by history-taking.