胸部リンパ節病変の診断における超音波気管支内視鏡ガイド 下経気管支針生検(EBUS-TBNA)の有用性

近年,超音波気管支内視鏡ガイド下経気管支針生検(Endobronchial Ultrasonography-guided Transbronchial Needle Aspiration,以下EBUS-TBNA)は縦隔および肺門リンパ節病変に対するアプローチ法として開発され,病理学的および微生物学的な確定診断に用いられる.EBUSTBNAを実施できるか否かの判断や,施行後の診断率には標的リンパ節の大きさや周囲もしくは内部血管などが影響するが,それらに関する報告は少ない.2010年10月～2013年8月に,当科でEBUSを施行した69例のTBNA施行率,診断率,不成功の理由を後方視的に検討した.TBNAを施行できたのは60例であり(87%),そのうち54例(93%)で診断が確定できた.肺癌が42例(67%)と最多で,以下サルコイドーシス7例,他臓器癌のリンパ節転移3例,抗酸菌感染症1例,悪性リンパ腫1例であった.EBUS施行例のリンパ節の直径は21.3±6.0mmで,非確診例の標的リンパ節は有意に小さかった(17.5±3.7vs22.9±5.1mm,p<0.0001).部位別では下部気管傍リンパ節と気管支分岐部リンパ節で実施した症例が多かったが,部位による診断率の差は認めなかった.最終診断率では,肺癌が91%(46例中42例),サルコイドーシスが70%(10例中7例)であった.TBNAの不成功の理由は,「標的リンパ節が小さい」,「血管損傷の可能性が高い」,「患者の鎮静不可」であった.重篤な有害事象は1例も認めなかった.縦隔および肺門リンパ節病変の診断において,EBUS-TBNAは有用であると考えられた.Endobronchial ultrasonography - guided transbronchial needle aspiration (EBUSTBNA) is a new method for tissue biopsy of thoracic lymph node lesion. However, the clinical usefulness of this method and associated issues are still relatively unknown. Sixty-nine cases received EBUS in our hospital between October 2010 and August 2013. The relationship was analyzed between the diagnostic rate and the size or location of the lymph node targeted. TBNA was performed in 60 of the 69 cases, out of those the pathological and microbiological diagnosis were obtained in 54 cases (93%). The final diagnosis consisted of lung cancer in 42 cases (67%) followed by sarcoidosis in 7, metastasis of the other organ\u27s malignancy in 3 and mycobacterium infection in 1, and lastly malignant lymphoma in 1. The mean lymph node diameter was 21.3 ± 6.0 mm, and the inability to obtain the correct diagnosis was significantly smaller than obtaining the correct diagnosis. (17.5 ± 3.7 vs 22.9 ± 5.1 mm, p < 0.0001). In regard to the location of the lymph nodes, "lower paratrachea" and " subcarinal" were common, but was not chief concern with the diagnostic rate. Futhermore, the diagnostic rate was 91% (42 of 46) in lung cancer and 70% (7 of 10) in sarcoidosis. We could not perform EBUS-TBNA because of "small lymphnode" and "high risk of vascular damage" in addition to "insufficient patient\u27s sedation". No severe adverse events had occurred. EBUS-TBNA is useful for the thoracic lymph node lesion diagnosis