膀胱憩室内に発生した小細胞癌の1例  [in Japanese] A CASE OF SMALL CELL CARCINOMA IN A DIVERTICULUM OF THE BLADDER  [in Japanese]

我々は,膀胱憩室内に発生した小細胞癌の1例を経験したので報告する.症例は64歳男性,尿閉を主訴に来院.膀胱鏡検査で右側壁の砲室内に乳頭状腫瘍を認め,膀胱憩室内腫瘍との診断で膀胱部分切除術を行い,腫瘍を憩室ごと切除した.病理組織診断は小細胞癌と移行上皮癌の併存している所見であり,前者が優位であった.膀胱憩室内腫瘍は,診断が困難な上に憩室壁が菲薄で壁外浸潤をきたしやすいため進行癌になりやすく,一般に予後不良である.一方,膀胱小細胞癌は極めて予後不良な,稀な膀胱癌組織型として知られている.膀胱憩室内に発生した小細胞癌は極めて稀で,我々が調べた限りでは本症例が本邦2例目である.

We report a case of small cell carcinoma in a diverticulum of the bladder. A 64-year-old Japanese man visited our hospital with the chief complaint of urinary retention. Cystoscopy revealed a papillary tumor arising in a diverticulum on the right lateral wall of the bladder. Partial cystectomy was performed under the diagnosis of bladder cancer in the diverticulum. The histopathological diagnosis was a combination of small cell carcinoma and urothelial carcinoma, of which the former was dominant. It is often difficult to detect tumors in the bladder diverticula and its early penetration is not rare because of the thin wall. Therefore, the prognosis of the bladder cancer in the diverticulum is believed to be generally poor. On the other hand, small cell carcinoma originating in the urinary bladder is also characterized by its extreme rareness and poor prognosis. To our knowledge, this is the second case report of the small cell carcinoma arising in a diverticulum of the urinary bladder in the Japanese literature.