泉 学¹, 藤原 理佐子¹, 小野 幸彦¹, 熊谷 富美子², 佐藤 匡也³, 庄司 亮³, 熊谷 肇³, 大阪 孝子⁴, 菊池 藍⁴, 鬼平 聡⁵

Manabu IZUMI¹, Risako FUJIWARA¹, Yukihiko ONO¹, Fumiko KUMAGAI², Tadaya SATO³, Akira SYOJI³, Hajime KUMAGAI³, Koko OSAKA⁴, Ai KIKUCHI⁴, Satoshi KIBIRA⁵

¹秋田県立脳血管研究センター内科循環器科, ²秋田県立脳血管研究センター臨床検査科, ³秋田県成人病医療センター循環器科, ⁴秋田県成人病医療センター医療技術部, ⁵きびら内科クリニック

¹Department of Cardiology,Division of Internal Medicine,Research Institute for Brain and Blood Vessels-Akita, ²Department of Clinical Laboratory,Research Institute for Brain and Blood Vessels-Akita, ³Department of Cardiology,Akita Medical Center, ⁴Department of Medical Technology,Akita Medical Center, ⁵Kibira Medical Clinic

キーワード : echocardiography, right ventricular outflow tract, thrombus, pulmonary embolism

心臓超音波検査法（以下心エコー）において，心腔内に血栓や腫瘍を認める場合がある．その際，塞栓症や外科的な治療を要する必要があり，特に左心房においては，血栓や粘液腫などが心原性脳塞栓症などの原因となるため，素早く的確な判断が必要である．しかし，右心系に関する血栓や腫瘍の報告は少ない．我々が経験した症例は，左片麻痺で発症した脳梗塞であるが，脳塞栓症が疑われたため，発症12病日に原因精査として行った心エコーで，右室流出路に約3.5cm長の可動性に富んだhyperechoic massを認めた．肺血流シンチで右下葉に一部欠損が認められ，併せてMRIでは茎のような付着点を流出路に持つmassが確認出来たため，腫瘍性の病変および血栓の両方の可能性を考えながら，外科的摘出術を考慮して抗凝固療法を行っていたところ，massの消失を認めた．下肢静脈エコーでは，左ヒラメ筋内静脈の拡張を認めた．経過からヒラメ静脈血栓がリハビリとともに右心室内に達し，付着していたと考えられた．消失してからの心エコーでは，右心系の負荷所見を認めず，さらに流出路に留まった器質的な原因を指摘出来なかった．右心系の中でも稀とされる右室流出路に血栓を認め，診断に苦慮したが，良好な転記を得たので報告する．

A 72-year-old man came to our hospital complaining of left hemiplegia. Acute ischemic stroke and occlusion of right middle cerebral artery were diagnosed, and conservative medical management was initiated. On the 13th day of hospitalization, echocardiographic examination showed a 0.8 × 0.8 × 3.5 cm mobile hyperechoic mass attached to right ventricular outflow tract (RVOT), but no chest symptoms were presented. While MRI also showed two stalks attaching the mass to the right ventricular outflow tract, we found it difficult to decide between thrombus and tumor. Because the mass was large enough to cause pulmonary embolism, we started administering unfractionated heparin and oral anticoagulant while considering surgical removal of the mass. Perfusion lung scintigraphy showed small defects in right lung fields. Subsequent transesophageal echocardiography showed disappearance of the tumor to be vanishing. The patient had no chest symptoms or thromboembolic complications. Lower leg venous echocardiography showed dilated veins in his left musculus soleus. We considered thrombus with a netlike structure moved from the left musculus soleus to the right ventricular outflow tract. In this patient, echocardiography was useful in making a differential diagnosis and in observing its clinical course.