急性心筋梗塞類似の心電図所見を示し，心エコー上心筋内腫瘤を認めた肺癌の心筋転移の1例

Report of a case of lung cancer with metastasis to the myocardium which showed electrocardiographic findings similar to acute myocardial infarction and intramyocardial mass on echocardiography

　悪性腫瘍患者剖検例で，心臓転移は1.5〜21％の頻度で認められるが，特に肺癌患者では心臓転移は高率で18〜36％と報告されている^1）。一方，剖検例の心臓転移の形成部位については心外膜が圧倒的に多く，50.4％ついで心筋が12.6％と報告されている^2）。しかし，心筋転移を生前に診断し得た症例の報告は少なく，心筋転移時の病態生理学的変化については不明な点が多く残されている。

　著者らは，心電図ならびに心エコー所見より生前に診断し得た心筋内肺癌転移の1例を経験したので，文献的考察を加えて報告する。

A 61-year-old man was admitted to our hospital with complaints of cough and left back and chest pain. He had suffered from left tuberculous pluerisy at the age of 20 years. Chest X-ray film and CT revealed atelectasis of the left lung, a left hilar mass and an irregular left atrial wall. Depressed P-Ta segment in the inferior limb and anterior chest leads and an abnormal P wave were found on ECG. Transbronchial lung biopsy showed squamous cell carcinoma. After radiation therapy, the patient complained of chest oppression. ECG revealed a normalized P-Ta segment deviation, markedly ele-vated ST segment in the inferior limb and lateral chest leads and a depressed ST segment in the anterior chest leads. These findings persisted until his death. An obscure appearance of the pericardium and an echogenic intramyocardial mass in the post-eroinferior and lateral wall were evident by echocar-diography. The patient died due to heart failure. Postmortem needle biopsy showed scattered intra-myocardial tumor cell nests with keratinization. CPK, GOT and LDH were within normal limits throughout the course, but CPK-MB was slightly increased.

Cardiac metastasis with an ECG appearance similar to that of acute myocardial infarction has been rarely reported. Our present case showed peculiar feature including 1) ECG findings similar to atrial and ventricular myocardial infarction, and 2) an echogenic intramyocardial mass and an ill-defined pericardium on echocardiography. These findings suggested direct invasion of squamous cell carcinoma of the lung to the atrial and ventricular myocar-dium. Although myocardial metastasis is relatively rare, its occurrence in the present patient was thought to have been due to the influence of tuber-culous pleurisy and radiation therapy.