腎門部領域と腎実質の2カ所に同時に認められた炎症性筋繊維芽細胞性腫瘍の1例

Abstract

61歳, 男。腹痛を主訴とした。腹部CTでは右腎下極に造影不良な2cm大の腫瘤を認め, MRIではT1, T2ともに軽度高信号を示し, 造影不良な腫瘤として認めた。鏡視下右腎尿管全摘術を施行し, 腎門部脂肪組織内に3.2cm大の硬い灰白色調の腫瘤を認め, 腎実質に進展していた。また, 腎上極の実質内にも1.4cm大の腫瘤を認め, 腎盂粘膜は平滑であった。病理所見では炎症細胞浸潤を背景に紡錘形の筋線維芽細胞の増生を認め, 緻密な膠原線維の沈着を伴っていた。後腹膜と右腎実質の2ヶ所に認めた炎症性筋線維芽細胞性腫瘍と診断した。経過良好で術後3ヵ月現在, 転移再発は認めていない。

A 61-year-old man consulted his local physician because of abdominal pain and was referred to our hospital after bilateral renal tumors were suspected on CT. CT and MRI showed a tumor, approximately 3 cm in diameter in the right renal pelvis and a cyst in the left kidney. There were no malignant cells detected on cytological studies of two urine specimens that were voided commonly and obtained from the right renal pelvis, respectively. Under a diagnosis of right renal pelvic tumor, the patient underwent laparoscopic right nephroureterectomy. Pathological examination demonstrated two inflammatory myofibroblastic tumors; one was located in the upper portion of the right kidney and the other was in the fatty tissue of the right renal hilus. There has not been any evidence of recurrence detected on follow-up for three months postoperatively.