腎Angiomyolipoma-診断と治療

Abstract

過去10年間に経験した腎angiomyolipoma14例の統計的検討を行い, これを含め1994年10月までの本邦報告例計739例の統計的考察を行った. 1)脂肪成分の検出率は, US, CT, MRIで, それぞれ88.1%, 86.5%, 80.8%の高率であった.Angiographyでは, AMLに特徴的とされる動脈瘤は71.4%に, A-V shuntの欠如は48.1%と半分以下に記載があるにすぎず, onion peel appearanceにいたっては, わずか4.9%であった. 2)小腫瘤, 脂肪成分の少ない例などの鑑別困難例も多く, また腎癌との合併例などの可能性も考慮し, AMLの画像診断はangiographyをも含め総合的に行うべきと思われた. 3)経過観察可能の症例は, 明らかに脂肪成分を認め, 無症状で, 腫瘍の大きさは3cm未満とした方がよい. 4)最近では, 腎摘出術の割合は30%まで低下してきており, 代わって経過観察が増加していた

In 10 years the diagnosis of renal angiomyolipoma (RAML) was made in 14 patients (male-to female ratio 1:3.7) at our institution; 1 case was associated with tuberous sclerosis (TS) and 1 case had regional lymph node involvement. A statistical study was done on data taken from 739 cases of RAML in the Japanese literature, including our cases. The male to female ratio was 1 to 3. Twenty eight percent of the cases were associated with TS. The ratio of bilateral cases to the unilateral one was 1 to 3. The main clinical signs were flank pain, abdominal mass, hematuria and fever elevation. Recently the ratio of nephrectomy has decreased to 30%. The percentage of detecting the fat component by ultrasonography (US), computed tomography (CT) and magnetic resonance imaging were 88.1%, 86.5% and 80.8% respectively. The percentages of visualizing hypervascularity, aneurysms, absence of arterio-venous shunt and onion peel appearance by selective renal angiography were 77.3%, 71.4%, 48.1% and 4.9% respectively. Small (less than 3 cm), asymptomatic, simple lesions with adipose component may be observed annually by CT and US until more experiences is gained with surveillance of these patients. Embolization was useful for emergency cases or pre-treatment of nephron sparing surgery, but insufficient by itself. As there still remain problems in the diagnosis of RAML, especially in the case of very small tumors, in the case with almost no adipose component and in the case associated with renal cell carcinoma, the diagnosis of RAML should be made synthetically including angiography.