移行上皮癌切除後に発生した膀胱小細胞癌

Small cell carcinoma of the urinary bladder occurring after resection of transitional cell carcinoma

　症例は75歳，男性。2000年6月肉眼的血尿にて当科を初診した。表在性膀胱腫瘍の診断下にTURBTを施行した（移行上皮癌）。以後の経過観察中，2003年1月の膀胱鏡検査で，膀胱右側壁に以前とは形態が異なる約2cmの隆起性病変を認め，生検で膀胱小細胞癌が疑われた。2003年4月に膀胱全摘除術を施行し，病理組織検査にて膀胱小細胞癌（pT3aN0M0）と診断された。術後CBDCA・VP-16併用化学療法を1コース施行した。8か月経過した現在，再発なく外来通院中である。

The patient was a 75-year-old man who initially presented with macrohematuria. Transurethral resection of bladder tumor（TURBT）was performed four times for superficial bladder tumor which revealed to be papillary transitional cell carcinoma（TCC）by histological examination. Follow-up cystoscopy two years and a half after initial TURBT showed a non-papillary tumor resembling submucosal tumor on the right wall of the urinary bladder. Transabdominal ultrasound,CT,and MRI showed a mass measuring about 2cm on the right wall of the bladder. Transurethral biopsy of the mass was performed,and histological examination revealed small cell carcinoma. Lymph node swelling and distant metastasis were not detected by MRI,CT. Radical cystectomy was performed. Histological and immunohistochemical examination of the cystectomy specimen revealed small cell carcinoma without TCC. One course of chemotherapy using carboplatin and etoposide was performed. At the 8months after the cystectomy,the patient was healthy without evidence of recurrence or metastasis.