膀胱内再発を認めた腎細胞癌の2例  [in Japanese] BLADDER RECURRENCE OF RENAL CELL CARCINOMA : REPORT OF TWO CASES  [in Japanese]

腎細胞癌が膀胱に転移することは珍しく,現在までに本邦では約30例が報告されているに過ぎない.今回2例の膀胱転移を経験したので報告する.症例1は87歳女性で,17年前に右腎細胞癌に対し根治的腎摘除術を受けた.2週間前頃より食欲低下・嘔気があり,内科を受診したところ,高カルシウム血症が発見された.更に精査したところ,多発性骨転移および非乳頭状有茎性の膀胱腫瘍が発見された.経尿道的切除術を施行したところ,組織学的に粘膜に限局した淡明細胞癌であり,17年前の腎細胞癌の転移であると考えられた.症例2は67歳男性で,4年前に左腎細胞癌に対し根治術が施行された.その後,免疫療法が行われたにもかかわらず多発注肺転移が出現した.1ヵ月前より無症候性肉眼的血尿が出現したため,精査したところ3個の非乳頭状有茎性の膀胱腫瘍が発見された.経尿道的切除術を施行したところ,組織学的に粘膜に限局した淡明細砲塔であり,4年前の腎細胞癌の転移であると考えられた.本報告の2例はいずれも粘膜に限局する再発であることから,尿路内の播種・implantationがその機序として最も疑われた.

We present two rare cases with renal cell carcinoma which recurred at urinary bladder. The first case is an 87-year-old female who had been undertaken right nephrectomy 17 years earlier. Through the examination of hypercalcemia, bone metastases and a bladder tumor were found. Transurethral resection of the bladder tumor was performed and histological examination revealed that the tumor was clear cell carcinoma similar to the right renal tumor. The second case is a 67-year-old male who had been undertaken left nephrectomy 4 and half years earlier. In spite of the adjuvant immunotherapy including interferon alpha, gamma and interleukin-2,16 months later multiple lung metastases appeared. One month before admission he noticed asymptomatic hematuria. Cystoscopy revealed 3 non-papillary pedunculated tumors, which were resected transurethrally. Histologically the tumor was clear cell carcinoma similar to the left renal tumor. In both cases the metastasis was confirmed histologically. As in both cases the recurrent bladder cancers were confined in the mucosa, these metastases were thought to be caused by implantation.