腫瘤形成性白血病による水腎症を呈したと考えられた馬蹄鉄腎

A Horseshoe Kidney with Unilateral Hydronephrosis Caused by Tumor-forming Leukemia

　症例は47歳，男性。慢性骨髄性白血病にて内科入院中，左腰痛にて当科を紹介され受診した。CTでは馬蹄鉄腎，左水腎症と左腎から腎盂にかけて長径2.0cmの腫瘤性病変を認めた。2週間後のCTにて急速な腫瘤の増殖を認め，骨髄穿刺にて急性転化を確認したため腫瘤形成性白血病と考え，内科にて化学療法を開始した。化学療法終了後，腫瘤と水腎症は消失し，腰痛も訴えていない。

The patient was a 47-year-old man who was referred to our department because of left low back pain while he was hospitalized at the department of internal medicine for the treatment of chronic myelogenous leukemia. CT revealed the presence of horseshoe kidneys, left hydronephrosis,and tumorous lesion measuring 2.0cm at the left kidney and renal pelvis. Two weeks later, CT revealed rapid grwth of the tumor, and blastic crisis of leukemia was confirmed by bone marrow puncture. Therefore, tumor-forming leukemia was suspected, and chemotherapy for leukemia was initiated.