術前診断困難であった骨盤内副脾の1例

A case of pelvic accessory spleens which were difficult to diagnose preoperatively

◆要旨：患者は79歳，女性．腹部超音波検査で偶然に腹腔内多発腫瘤を指摘された．CTにて腹部骨盤内に左胃大網動脈分枝と連続する血管から栄養される44mm大の強い造影効果を持つ腫瘤を認め，同血管沿いに9mm，11mmの同様の腫瘤を認めた．MRIを施行したが診断に至らず，診断目的で腹腔鏡下腫瘤摘出術を施行した．左下腹部に40mm大の黄色調の白苔に覆われた腫瘤を認め，同腫瘤より左胃大網動脈に向かい血管が伸びており，中途で血管の蛇行・拡張があった．胃大彎に10mm大の褐色腫瘤を認めた．病理診断ではいずれも副脾であり，拡張・蛇行した血管は動静脈瘻であった．骨盤内副脾は稀だが，その診断には,栄養血管の走行を検討することが有効と考えられた．

The patient is a 79-year-old woman. Abdominal ultrasonography revealed multiple masses. Computed tomography（CT） revealed an enhanced mass, 44mm in diameter, in the left side of the pelvis, with blood supply from a branch of left gastroepiploic artery. Along the feeding artery there were two similar masses, 10mm in diameter. Because of difficulty diagnosing by magnetic resonance imaging（MRI）, laparoscopic excision was performed. A 40mm mass was located in the left side of the lower abdomen and the vascular pedicle, which was tortuous and partly dilated, was from the left gastroepiploic artery. In addition, a 10mm mass was noted along the greater curvature of the stomach close to the spleen. The masses and the pedicle were excised. Histopathologic examination revealed that the masses were accessory spleens ; the tortuous and dilatated vessel was arteriovenous malformation. Although pelvic accessory spleen is rare, our reported case was typical for pelvic accessory spleen.