河村 知史¹, 樋上 真由美¹, 児島 康行², 三宅 修³, 森本 章⁴, 磯田 幸太郎⁵, 宮田 和枝¹, 新名 正己¹, 田畑 勉⁶, 井上 隆⁶

Chifumi KAWAMURA¹, Mayumi HINOUE¹, Yasuyuki KOJIMA², Osamu MIYAKE³, Akira MORIMOTO⁴, Kotaro ISODA⁵, Kazue MIYATA¹, Masami SHINMEI¹, Tsutomu TABATA⁶, Takashi INOUE⁶

¹蒼龍会井上病院臨床検査課, ²蒼龍会井上病院泌尿器科, ³医誠会病院泌尿器科, ⁴蒼龍会井上病院放射線科, ⁵蒼龍会井上病院病理, ⁶蒼龍会井上病院内科

¹Clinical Laboratory, Inoue Hospital, ²Department of Urology, Inoue Hospital, ³Department of Urology Iseikai Hospital, ⁴Department of Radiology, Inoue Hospital, ⁵Department of Pathology, Inoue Hospital, ⁶Department of Internal Medicine, Inoue Hospital

キーワード : acquired renal cystic disease, contrast-enhanced ultrasonography, renal angiomyolipoma, renal cell carcinoma, renal oncocytoma

多嚢胞化萎縮腎に腎細胞癌が高頻度に合併することはよく知られており, 以前より我々は腎細胞癌との鑑別に造影超音波検査を行っている. 今回我々は定期スクリーニングにて見つかった, 腎細胞癌と鑑別困難であった, 多嚢胞化萎縮腎に合併した良性腎腫瘍の2例を経験したので報告した. 症例1は58歳女性で, 腹部CTにて左腎下極に異常影が指摘され, 精査の結果左腎細胞癌が否定できず, 後腹膜鏡下左腎摘除術を施行した. 病理結果は脂肪成分の少ない腎血管筋脂肪腫であった. 症例2は75歳女性で, 腹部CTにて右腎中央に異常陰影が指摘され, 精査の結果右腎細胞癌が否定できず, 後腹膜鏡下右腎摘除術を施行した. 病理結果はオンコサイトーマであった. 多嚢胞化萎縮腎にこれら良性腫瘍が合併することは稀であり, 今回retrospectiveに造影超音波検査の結果を検討した. 脂肪成分の少ない腎血管筋脂肪腫の造影超音波検査では, 腎細胞癌で見られる腫瘍辺縁を取り囲む血流は認めず, 腫瘍の内部に拡張・蛇行した血管が辺縁から中心へ向かって, 蜘蛛の巣状に濃染されるパターンを呈していた. オンコサイトーマでは腫瘍の辺縁から濃染し始め腫瘍全体に著明な造影効果を認め腎細胞癌との鑑別は困難であった.

Because acquired renal cystic disease is frequently complicated by renal cell carcinoma (RCC), we used contrast-enhanced ultrasonography to differentiate between benign tumors and renal cell carcinomas. Here we report two cases of benign renal tumors accompanying acquired renal cystic disease that were detected on periodic screening and were difficult to differentiate from renal cell carcinomas. Case 1 was presented by a woman aged 58 years. Abdominal computed tomography (CT) revealed an abnormal shadow in the lower pole of the left kidney, and because a detailed examination did not rule out left renal cell carcinoma, retroperitoneoscopic left nephrectomy was carried out. Pathologic findings suggested renal angiomyolipoma with minimal fat content. Case 2 was presented by a woman aged 75 years. Abdominal CT revealed an abnormal shadow at the center of the right kidney, and again, because a detailed examination did not rule out renal cell carcinoma in the right kidney, retroperitoneoscopic nephrectomy was carried out. The pathologic findings suggested renal oncocytoma. These benign tumors rarely accompany acquired renal cystic disease, and in this study, we retrospectively investigated the results of contrastenhanced ultrasonography. Contrast-enhanced ultrasonography of renal angiomyolipomas with minimal fat showed no blood flow surrounding the surrounding periphery of the tumor, a typical finding in cases of renal cell carcinoma. Also, dilated tortuous blood vessels in the tumor were darkly enhanced and resembled a spider's web extending inward from the periphery of the lesion. In the renal oncocytoma lesion, the entire tumor, including its margin, was markedly enhanced, and the lesion was difficult to differentiate from renal cell carcinoma.