偶発的に発見された空腸間膜仮性嚢胞の1例

An incidentally discovered case of jejunum mesenteric pseudocyst

腸間膜嚢胞はリンパ管腫がほとんどとされており^1），腸間膜仮性嚢胞の報告はまれである。腸間膜嚢胞は，極めてまれながら悪性例や再発の報告もあり^2）3），嚢胞の完全切除が望まれるため^3），術前診断は重要である。リンパ管腫の画像的特徴については多くの検討がなされてきたが，腸間膜仮性嚢胞の画像的特徴について検討した文献は少ない。今回我々は，典型的な空腸間膜仮性嚢胞の1例を経験したので，我が国での32の症例報告を交えて腸間膜仮性嚢胞の画像的特徴について報告する。

A woman in her 50s undergoing evaluation for right upper quadrant pain was found to have cholelithiasis and a hepatic hemangioma on ultrasonography. Subsequent MRI incidentally detected a 91 mm mass on the ventral aspect of the pancreatic tail, initially suspected to be a retroperitoneal teratoma. Contrast-enhanced CT demonstrated a well-defined, unilocular cystic lesion within the jejunal mesentery, characterized by a homogeneous, gradually enhancing wall, absence of internal enhancement, and a fat-fluid level. MRI suggested lipid and hemorrhagic components within the cyst. Surgical resection, including partial duodenal and jejunal resection, was performed, and histopathological examination confirmed a mesenteric pseudocyst. Review of 32 reported cases in Japan indicated that these imaging features are relatively typical. A mesenteric pseudocyst should be considered a key differential diagnosis for a unilocular cystic lesion in the jejunal mesentery.