虫垂病変の臨床―画像診断―X線・内視鏡診断の立場から

Diagnosis of Appendiceal Disorders by Barium Enema X-ray and Colonoscopy

要旨　虫垂には他の大腸と同様にさまざまな疾患がみられるが，虫垂粘液囊腫のような特異的な病変も存在する．虫垂は極めて狭い管腔臓器であり，病変を注腸X線造影検査，大腸内視鏡検査で観察することは難しい．また，病変の存在によって虫垂炎を来し，虫垂切除後に，病理診断がなされることが多い．診断に際しては，切除歴がないにもかかわらず，注腸X線造影検査で虫垂が描出されないことを異常としてとらえることが重要である．病変を直接観察できない場合は，圧排，変形，伸展不良，粘膜下腫瘍様所見などの間接的所見を読影する必要がある．また，腫瘤性病変の診断において，さまざまな程度に合併する虫垂重積症の所見を理解することも大切である．

　Appendiceal disorders cover a wide spectrum. They include general disorders of the large intestine and those specific to the appendix, such as mucoceles. The presence of lesions increases the chance of developing appendicitis ; however, visualization of appendiceal lesions by barium enema X-ray or colonoscopy is difficult due to the extremely narrow lumen of the appendix. Consequently, formal diagnoses are often only made pathologically. If an appendix is not visualized during barium enema in patients without prior appendectomy, the presence of appendiceal lesions should be considered. When lesions are not directly observed, indirect barium findings must be carefully evaluated, including external compression, deformity, poor distensibility, and a submucosal tumor-like appearance. When diagnosing mass-forming lesions of the appendix, it is important to recognize the various degrees of appendiceal intussusception.