A 28-year-old female complained of minimal fever elevation. Computed tomography (CT) revealed a left renal tumor of 10 cm diameter. Ultrasonogram and CT, magnetic resonance imaging and angiography suggested a renal angiomyolipoma (AML) with marked extrarenal development. Partial nephrectomy was performed using a microwave tissue coagulater without clamping of the renal artery. The tumor weight was 800 g and the pathological diagnosis was AML. The management of large AML is reviewed in the literature. Nephron sparing surgery should be performed even in patients who have a large tumor with extrarenal development.

症例は２８歳女性で，発熱のため受診し，ＣＴで左腎上極に腫りゅうが認められた。著明な腎外発育を伴った腎血管筋脂肪腫の術前診断で，左腎部分切除術を施行した。腫ようは腎上極前面に位置し，周囲との境界は明瞭で，ひ蔵，すい蔵からも容易に剥離が可能で合った。マイクロターゼを用いて腫ようと腎の境界を全周性に凝固し，非阻血で腎部分切除を施行した。摘出標本は重量８００ｍｇ，滑面は黄白色で内部不均一な充実性腫ようであった。

Renal angiomyolipoma, Extrarenal development, Partial nephrectomy
腎臓腫よう；腎臓切除；良性腫よう；症例報告；ヒト
M.S. KIDNEY