Online ISSN: 2187-2988 Print ISSN: 0911-1794
特定非営利活動法人日本小児循環器学会 Japanese Society of Pediatric Cardiology and Cardiac Surgery
Pediatric Cardiology and Cardiac Surgery 31(6): 347-351 (2015)

症例報告Case Report

無症候性左心耳瘤の病理組織学的検討Histopathological Findings of Asymptomatic Left Atrial Appendage Aneurysm

1島根大学医学部小児科学教室Department of Pediatrics, Faculty of Medicine, Shimane University ◇ 〒693-8501 島根県出雲市塩冶町89番地1Enya-cho 89-1, Izumo-shi, Shimane 693-8501, Japan

2島根大学医学部心臓血管外科学教室Department of Cardiovascular Surgery, Faculty of Medicine, Shimane University ◇ 〒693-8501 島根県出雲市塩冶町89番地1Enya-cho 89-1, Izumo-shi, Shimane 693-8501, Japan

受付日:2015年4月25日Received: April 25, 2015
受理日:2015年8月28日Accepted: August 28, 2015
発行日:2015年11月1日Published: November 1, 2015

左心耳瘤(left atrial appendage aneurysm, LAAA)は,1938年にSemansとTaussigにより初めて報告された非常に稀な疾患で,先天性のものの多くは原因不明である.小児期に無症状で発見されると,将来的な不整脈,胸痛,呼吸困難,血栓塞栓症などの合併症予防のために外科的切除を行う.今回我々は,急性気管支炎の際に胸部レントゲン写真で異常を指摘された2歳女児におけるLAAAの症例を経験した.経胸壁エコー,経食道エコー検査を行い,瘤内や心耳内血栓を否定した.また造影CTにて周囲に異常構造がないことを確認した.手術により切除した病理組織において,三層構造は保たれていたが,筋層の菲薄化と粘液性変化がみられた.恒常性を維持させられないほどの組織障害が生じたことが,瘤の原因となりえた可能性が示唆された.

Semans and Taussig first described congenital left atrial appendage aneurysm (LAAA) in 1938. However, it is very rare and has seldom been reported. The congenital reasons for its development are unknown. Although it is asymptomatic during the infantile period, it is usually resected in order to prevent symptoms that are commonly associated with it, including supraventricular arrhythmia, compression of the coronary arteries, dyspnea, intracardiac thrombus, and pulmonary venous stenosis. Here we report on the surgical management of an asymptomatic 2-year-old girl with this anomaly. Transthoracic and transesophageal echocardiography did not reveal thrombosis in the left appendage, and contrast-enhanced computed tomography of the LAAA demonstrated no abnormal structures. After median sternotomy, aneurysmectomy was performed under cardiopulmonary bypass without cross-clamping. The patient underwent successful surgical resection of the aneurysm.

Pathological examination revealed the three levels of atrial structure epicardial, myocardial, and endocardial layers; thinning of the muscular layer; and mucous degeneration, classifying the LAAA into an intrapericardial aneurysm of the left atrial appendage. Tissue destruction and the inability to maintain tissue homeostasis may have contributed to the formation of the LAAA.

Key words: left atrial appendage aneurysm; congenital; asymptomatic; histopathology; mucous degeneration

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