123I-BMIPP心筋SPECTにより生前に心筋浸潤を診断しえた転移性心臓腫瘍の1例

A Case of Metastatic Cardiac Tumor Assessed by 123I-BMIPP Myocardial SPECT

　患者は69歳の女性で，頭痛を主訴に受診した．CTでは右肺S¹⁰領域，左前頭葉，右後頭葉，および両側副腎に腫瘍が認められた．心臓超音波検査では左心室腔内に腫瘍が認められた．脳腫瘍の組織診断では腺癌であった．肺腺癌の脳転移，両側副腎転移および左心室転移と診断された．²⁰¹T1心筋SPECTでは集積低下は認められず，左室心筋の肥厚および左室内腔の狭小化が認められた．¹²³I-BMIPP心筋SPECTでは，前壁および下後壁に高度な集積の低下，左室壁厚の菲薄化と左室内腔の拡大が認められた．心室細動により死亡した．理解剖では，腫瘤は左室内腔の大部分を占め，全周性の心内膜側からの浸潤も認められた．また，前壁の心筋内に腫瘍が認められた．T1は肺癌細胞に集積するため心筋内転移においても集積低下が認められず，左室心筋肥大の所見が認められたと考えられた．BMIPPは肺癌細胞には集積しないため，心筋内転移領域で高度な集積低下が認められたと考えられた．また，肺癌細胞が全周性に心内膜側より浸潤していたため，左室心筋の菲薄化や左室内腔の拡大所見が認められたと考えられた．転移性心筋腫瘍の非侵襲的評価に¹²³I-BMIPP心筋SPECTが有用と考えられた．

A 69-year-old woman visited our hospital because of headache. A brain computed tomography (CT) showed two coin lesions, one at the left frontal lobe and the other at the right posterior lobe. A chest CT showed a coin lesion at the right S¹⁰ region, and an abdominal CT showed tumors at the bilateral adrenal glands. An echocardiogram showed a giant mass in the left ventri-cle. An extracted specimen from the brain showed poorly differentiated adenocarcinoma. We diagnosed the patient as having primary lung cancer with brain, adrenal, and cardiac metastasis. ²⁰¹T1 myocardial SPECT showed normal uptake and left ventricular hypertrophy. ¹²³I-BMIPP myocardial SPECT showed reduced uptake at the anterior and posterior wall, left ventricular dilatation, and wall thinning. Through path-ological anatomy. it was found that a giant tumor occupied most of the left ventricle, and a solitary metastatic tumor was found in the myocardium at the anterior wall. Invasion of the tumor was observed throughout the left ventricle from the epicardium, and the degree of invasion was most severe in the posterior wall. ²⁰¹T1 myocardium SPECT showed left ventricular hypertrophy, because ²⁰¹T1 had accumulated in the lung cancer cell. ¹²³I-BMIPP had not accumulated in the lung cancer cell, so ¹²³I-BMIPP myocardial SPECT showed severely reduced uptake in the anterior wall, left ventricular dilatation and left ventricular wall thinning. These findings suggested that ¹²³I-BMIPP myocardial SPECT might be useful for the diagnosis and assessment of metastatic cardiac tumor.