左腎周囲に発生した後腹膜悪性リンパ腫の1例

Abstract

62歳女.腹部腫瘤を自覚し, 増大したため受診し, CTで左腎周囲より左骨盤腔に拡がる後腹膜腫瘍を指摘された.腫瘍マーカーではCA125が上昇していたが, 血算, 生化学的所見に異常はなかった.腹部CTで腎周囲に発生し, 左後腹膜腔を占拠する腫瘍性病変を認めた.腫瘍は境界明瞭で単純CTで, 均一で腎実質と同濃度, 造影CTで腎実質に比べ, 弱く造影された.また, 大動脈大静脈間リンパ節腫大も認められた.MRIT1強調, T2強調画像で腫瘍は内部均一な低信号強度を示した.CT上, 左尿管は腫瘍に取り囲まれていたが, DIP上は軽度の水腎症を認めるのみで, 尿管への浸潤所見はなかった.悪性リンパ腫を疑い, エコーガイド下に針生検を行った.腎および腎周囲原発の悪性リンパ腫は比較的稀な疾患であるが, 画像所見で疾患を疑い, 針生検で診断を確定, 治療することが可能と考えられた

We report a case of malignant lymphoma arising as a giant perirenal mass in a 62-year-old woman who presented with an enlarging abdominal mass. Computed tomography (CT) revealed a large homogeneous mass with a diameter of 20 cm arising in the retroperitoneum. It surrounded the left kidney without renal infiltration and accompanied with para-aortic lymph node enlargement. Compared with the renal cortex, the tumor showed a homogeneous isodense mass by plain CT and only slight enhancement by the contrast-enhanced CT. On the basis of these imaging studies, the tumor was diagnosed as lymphoma. Then, a US guided percutaneous biopsy was performed and the tumor was diagnosed as malignant B-cell lymphoma by the histopathological analysis. This patient was treated by systemic chemotherapy since tumor cells were also disseminated in the bone marrow. The tumor responded well to the chemotherapy and about 70% of regression was achieved after six courses of chemotherapy.