原発性アルドステロン症の5例 - 腫瘍局在診断に関する各種検査法の有用性について -

Abstract

原発性アルドステロン症の5例について各種検査法の有用性を検討した.1) CTでは, 全例にlow density areaを認め, 3例で明確に腺腫像を認めた.副腎シンチグラフィーでは, 3例で左右差を認め, さらにデキサメサゾン投与後の検査では, 正常部へのとりこみの抑制による左右差がより明確化した.静脈造影では, 血管走行の変化もしくは腺腫像として認められたのは1例にすぎなかったが, 同時に施行し得た静脈カテーテル法によって, 全例に局在診断が可能であった.2)以上より本症に対する局在診断のすすめかたとしては, 侵襲の少ない点から, CTもしくはシンチより行う, シンチの場合, デキサメゾン投与がさらに有用になると思われる.3)静脈造影は, 侵襲の大きさに比し, 診断率において劣るが, 同時に行える静脈カテーテル法によるアルドステロン測定は診断率が高く, 非常に有用であることから, 最終的には行われるべきであろう

Five cases of primary aldosteronism are reported, and several techniques to localize the tumor were evaluated. On computed tomography which is a noninvasive technique, low density areas were identified in all cases, and definite adenomas were clearly detected in three of five cases. Adrenal scintigraphy with 131I-19-iodocholesterol is another noninvasive technique that showed unilaterally increased uptake in two cases. Dexamethasone inhibits the uptake of labeled cholesterol by hyperplastic or normal glands but does not interfere with the uptake by an adenoma. Using this technique, it was possible to lateralize additionally the tumor in one case. Adrenal venography which is an invasive technique that showed a circular deformity with tumor depicted the tumor in only one case. However, the venous effluent was sampled simultaneously from both glands and the plasma aldosterone concentration in each sample assayed. An increase in aldosterone concentration on only one side localizes the aldosterone producing adenoma to that side. The method was highly accurate, and provided the correct diagnosis preoperatively in all cases. Being a noninvasive technique, computed tomography and adrenal scintigraphy should be undertaken initially, and venography coupled with measurements of aldosterone concentrations in the left and right adrenal venous effluent could be a definitive procedure before surgery.