腹部超音波とCTで特徴的所見を捉えた虫垂粘液球症の1例

Myxoglobulosis of the Appendix Showing Characteristic Findings Revealed by Ultrasonography and CT Scan, Report of a Case

要旨　まれな腫瘍である虫垂粘液球症を経験し，術前の腹部超音波と腹部CTでその特徴的所見を捉えた．患者は65歳，女性．検診目的で注腸X線を施行した．盲腸に輪状のはち巻きひだを有する直径4cmの半球状で表面平滑な腫瘤を認めた．盲腸壁の伸展性は良好で，虫垂は造影されなかった．腹部超音波では，腫瘤は盲腸下部から虫垂にまで連続しており，実質様エコーを呈し，内部に無数の点状高エコーを混じていた．腹部CTでも，腫瘤内部に無数の粒状の石灰化を認めた．回盲部切除術を施行した．腫瘤内腔には直径1mm前後の乳白色の粘液球が充満しており，PAS染色により年輪状の層構造が明らかとなった．組織学的には虫垂粘液囊胞腺腫であった．

　Myxoglobulosis is a rare morphologic variant of appendical mucocele characterized by intraluminal mucinous globules of the appendix. Most reported cases have presented clinically as an acute abdomen or as an incidental laparotomy or autopsy finding. We report a case of myxoglobulosis in a 65-year-old woman in whom ultrasonography and CT scan showed the characteristic findings of calcified globules. She was admitted to our hospital complaining of slight constipation. A barium enema examination demonstrated a hemispherical mass which had a smooth surface and “concentric head-band fold” in the cecum. The appendix was not seen. Colonoscopy revealed the same findings. Ultrasonography demonstrated “soft tissue”-like echo with numerous granular high echo in the lumen of the mass. Posterior echo of the mass was enhanced. CT scan also demonstrated numerous granular calcifications in the inner part of the mass. Laparotomy disclosed an enlarged appendix, 4 cm in diameter and 12 cm in length. The lumen was filled with numerous milky-white calcified globules about 1 mm in diameter. The globules consisted of PAS positive mucin showing concentric layers like an onion and necrotic remnants of cells. Histological diagnosis of the lesion was mucinous cystadenoma of the appendix.