病理解剖で明らかとなった肝内胆管癌からの腫瘍塞栓性肺微小血管障害の1例(Pulmonary tumor thrombotic microangiopathy caused by intrahepatic cholangiocarcinoma)

要旨 腫瘍塞栓性肺微小血管障害（pulmonary tumor thrombotic microangiopathy: PTTM）は，肺動脈腫瘍塞栓の特殊な型として報告された新しい疾患概念である。前医にて慢性閉塞性肺疾患に対するリハビリ目的で入院中の71歳男性が，突然の低酸素血症を伴うショックを呈し当院へ救急搬送となった。造影CT検査により肺塞栓症は否定されたが，来院6時間後，急速な酸素化障害から心停止に至りECMO（extracorporeal membranous oxygenation）を導入した。著明な肺高血圧状態にあることが判明したが，治療抵抗性であり入院8日目にECMO離脱困難のまま死亡となった。その後の病理組織診断にて肝内胆管癌由来のPTTMであることが判明した。PTTMは肺動脈内皮の増生を伴う腫瘍塞栓が特徴的な病態で，本症例のように急性増悪する肺高血圧症を認めた際に鑑別を要する病態と考えられる。 ABSTRACT Pulmonary tumor thrombotic microangiopathy (PTTM) is a new disease concept that has been reported as a specific type of pulmonary tumor embolism. A 71–year–old man who was undergoing rehabilitation for chronic obstructive pulmonary disease in a different hospital was transported to our hospital due to sudden shock with hypoxia. Initial CT examination was negative for acute pulmonary embolism. Six hours after admission, he went into cardiac arrest following rapid progression of impaired oxygenation, and percutaneous cardiopulmonary support was introduced. Remarkable pulmonary hypertension was identified that was intractable to treatment, and it eventually led to his death 8 days after admission. Subsequent pathological diagnosis revealed the presence of PTTM derived from intrahepatic cholangiocarcinoma. PTTM is characterized by tumor emboli accompanied by endothelial proliferation in the pulmonary vasculature. It should be considered as one differential diagnosis when a patient presents with acute progressive pulmonary hypertension as in this case.