自然消失を認めた膀胱原発小細胞癌

Spontaneous regression of small cell cancer of bladder : A case report

　74歳男性．頻尿を主訴に当科を受診した．膀胱腫瘍の診断で経尿道的膀胱腫瘍切除術（TUR-BT）を施行し，小細胞癌の診断となり，局所浸潤膀胱癌に対して根治的膀胱全摘除術を施行した．諸検査から残存病変は明らかであったにもかかわらず，摘出膀胱では悪性細胞を認めず，炎症細胞の浸潤のみを認め，癌の自然消失を認める結果となった．癌の自然消失の報告は散見されるが，膀胱癌に関してはまれである．

Abstract

A 74 year-old man presented with pollakisuria. Ultrasonography revealed a small mass arising from the left wall of the bladder. He underwent trans urethral resection of the bladder tumor (TUR-BT) and the tumor showed small cell carcinoma. The postoperative contrast enhanced computed tomography (CT) revealed residual bladder tumor and urine cytology after TUR-BT was class V, suggesting the presence of residual cancer in the bladder. We performed radical cystectomy, and pathology of the bladder revealed no malignant cells with only inflammatory cells. No recurrence has been observed for one year and five months. As spontaneous regression of cancer described by many authors, spontaneous regression of bladder cancer is rare. We reported a case of spontaneous regression of small cell cancer of the bladder (Rinsho Hinyokika 71 : 271-274, 2017).