BCG膀胱内注入療法後,特異な前立腺浸潤様式を来たした膀胱上皮内癌の1例

Abstract

41歳男.患者は頻尿および排尿時痛を主訴とし, 膀胱頸部を含む膀胱内に広範な膀胱上皮内癌(CIS)が認められた.BCG膀胱内注入療法が施行されたが, 尿細胞診ではclass IVが検出された.更にこの尿細胞が診陽性を持続するため, 経直腸的前立腺針生検を行った.その結果, 前立腺組織の先端部に尿路上皮癌(UC), G3が検出された.膀胱癌の前立腺浸潤と診断し, 尿度摘除を含めた膀胱前立腺全摘除術, 回腸導管造設術が施行された.病理組織像ではUC, G3が前立腺内に胞巣状に広がっており, 前立腺間質への浸潤が認められた.pT4aN0M0との診断で, 術後は補助化学療法が3コース施行された.1年8ヵ月現在, 再発の徴候は認められていない

We report a case of carcinoma in situ (CIS) of the bladder involving the prostate with an unusual invasive pattern following Bacillus Calmette Guerin (BCG) therapy. A 41-year-old man achieved complete response after a course of intravesical instillation of BCG for diffuse CIS of the bladder. Two years later, urine cytology became positive. We performed random biopsy of the bladder and urethra three times and examined the bilateral upper urinary tract with retrograde pyelography and split urine cytology. However, none of these examinations revealed any malignant features, leading to a suspicion that the prostate was the recurrent site. Transrectal needle biopsy of the prostate revealed urothelial carcinoma (UC) at the transition between bladder and prostate. Transurethral biopsy of the prostatic urethra also detected UC in a core of the bladder neck only. Under a diagnosis of UC involving the prostate, we performed total cystectomy with ileal conduit diversion. Histopathological findings of the surgical specimen showed prostatic stromal invasion of the tumor. In this case, CIS at the bladder neck might directly and silently invade the prostatic stroma, thus transurethral biopsy contributed little to the diganosis. We recommend transrectal needle biopsy of the prostate as well as TUR biopsy in such rare cases.