多発性膀胱Paragangliomaの1例

Abstract

77歳女。前腕の悪性黒色腫治療中のスクリーニングCTにて認めた膀胱内腫瘤を主訴とした。CTとMRIでは膀胱左側壁に5×4cm大の著明な造影効果を有する腫瘤を認めた。膀胱鏡検査で認めた左尿管口周囲から左側壁にかけての粘膜下腫瘍の生検と後壁の非乳頭状有茎性腫瘤に対する経尿道的膀胱腫瘍切除術を施行し, 生検の病理診断は膀胱paragangliomaであった。さらに血中・尿中カテコラミン高値と排尿時発作が確認され, 123IMIBGシンチで腫瘍に集積を認めたことから, 膀胱に限局した多発性paragangliomaと診断し, 左側壁の主病変に対する膀胱部分切除術を施行した。病理組織所見ではZellballen形態をなし悪性所見は認めなかった。術後6ヵ月時のCTにて切除範囲外の残存病変を認めたが, 2年経過現在も腫瘍の増大はなく自覚症状も出現していない。

A 77-year-old woman who was treated for malignant melanoma was incidentally found to have a bladder tumor on a screening computed tomography (CT). On CT and magnetic resonance imaging (MRI), the tumor was detected as a well-enhanced tumor (4 x 5 cm at horizontal plane) on the left side of the bladder wall. Cystoscopy revealed a small non-papillary pedunculated tumor on the posterior wall and a submucosal tumor on the left side of the wall. We performed transurethral resection of the tumor on the posterior wall and biopsy of the tumor on the left side wall. The pathological diagnosis was paraganglioma of the urinary bladder. Serum and urine levels of noradrenaline and dopamine were elevated. 123I-metaiodobenzylguanidine (MIBG) scintigraphy showed a significant uptake on the left side of the bladder. Blood pressure was normal at rest but elevated after micturition. No pelvic lymph node swelling or distant metastasis was detected. We performed partial cystectomy for the tumor on the left side wall. After operation, serum catecholamine level was normalized and post-voiding fatigue that was present before operation disappeared. Six months after operation, a followup CT revealed a small well-enhanced tumor on the anterior wall of the bladder. Her serum noradrenaline level was slightly elevated. However, she was normotensive and had no symptoms. Therefore, a careful follow-up continued for 2 years there after has revealed no increase in tumor size and no symptoms.