簑田 直樹¹, 多田 俊史², 松崎 俊樹¹, 住ノ江 功夫¹, 綿貫 裕³, 中村 進一郎²

Naoki MINODA¹, Toshifumi TADA², Toshiki MATSUZAKI¹, Isao SUMINOE¹, Yutaka WATANUKI³, Shinichirou NAKAMURA²

¹姫路赤十字病院検査技術部, ²姫路赤十字病院内科, ³奥新クリニック臨床検査科

¹Department of Clinical Laboratory, Japanese Red Cross Society Himeji Hospital, ²Department of Internal Medicine, Japanese Red Cross Society Himeji Hospital, ³Department of Clinical Laboratory, Okushin Clinic

キーワード : contrast-enhanced ultrasonography, diffuse liver metastasis, small cell lung cancer, liver disorder, high-frequency transducers

症例は70歳代女性，前医より急性肝炎もしくは急性胆管炎，そして肺門部腫瘤が疑われ，精査加療目的に当院紹介となった．各種血液検査では軽度の貧血，肝胆道系酵素の上昇，炎症反応の軽度上昇が認められた．超音波検査（Bモード）では肝両葉は著明に腫大し，肝表面に近い肝臓実質内に厚みのある辺縁低エコー帯を伴う低～等エコー腫瘤が散在していた．造影超音波検査（後血管相）のコンベックスプローブの観察では，肝臓内に最大8 mm大の欠損像が多数認められた．さらに造影超音波検査（後血管相）のリニアプローブの観察では，肝臓内に無数の微小な欠損像が認められた．腫瘍マーカーはNSE: 562.0 ng/mL，ProGRP: 36,325.4 pg/mLで高値であった．気管支鏡検査による縦隔リンパ節の細胞診の所見は小細胞肺癌のリンパ節転移であった．造影超音波検査（後血管相）においてリニアプローブを使用することで，肝臓内にコンベックスプローブでは不明瞭であった無数の微小な欠損像を指摘でき，腫瘍マーカーと合わせて，小細胞肺癌のびまん性肝転移と診断できた．原因不明の肝障害で，背景に悪性疾患が疑われ，Bモードで肝腫大や腫瘤性病変を指摘した場合，びまん性肝転移も鑑別に挙げる必要がある．そして検査者は臨床側に造影超音波検査での精査を進言することで，迅速な診断の一助になり得ると考えられた．

A woman in her seventies, who was suspected of acute hepatitis or acute cholangitis and tumor of pulmonary hilar lesion at another hospital, was referred to our hospital for detailed examination and treatment. Laboratory examination showed mild anemia, high hepatobiliary enzyme levels, and mild inflammatory findings. On B-mode US, the liver was markedly swollen at both lobes, with low to isoechoic tumors with halo in the liver parenchyma near the surface. Contrast-enhanced ultrasonography (post-vascular phase) observation with a convex probe revealed a large number of defects up to 8 mm in size in the liver. Furthermore, contrast-enhanced ultrasonography (post-vascular phase) observation of with a linear probe revealed innumerable minute defects in the liver. Tumor markers NSE and ProGRP were 562.0 ng/mL and 36,325.4 pg/mL, respectively. Mediastinal lymph nodes were punctured using bronchoscopy. Fine-needle aspiration cytology revealed lymph node metastasis from small cell lung cancer. By using contrast-enhanced ultrasonography (post-vascular phase) with a linear probe, we could detect innumerable minute defects in the liver that were unclear with a convex probe. They were diagnosed as diffuse liver metastasis from small cell lung cancer based on the assessment of tumor markers. In cases with an unknown liver disorder, if a malignant disease is suspected and we can detect hepatomegaly or liver tumor on B-mode US, it is necessary to distinguish diffuse liver metastasis. The suggestion of CEUS examination from the examiner to the physician could help early diagnosis of diffuse liver metastasis.