大腸直腸的小細胞癌極其少見,它確實發生的百分比率尚不很清楚,但應只佔所有大腸直腸惡性腫瘤的0.2%以下。小細胞癌的臨床表現極其惡性,進展很快,大部份病例診斷出來時,均已有肝臟或其他部位轉移,因此預後很差。平均診斷後只能存活6個月,一年的存活比率小於15%。治療上以多種混合化療為主,少部分如同肺小細胞癌一樣,對化療反應甚佳。對於腫瘤小且顯然沒有轉移的早期病例,可考慮根治性切除,加上術後化學藥物治療,有機會達到痊癒。本病例是一58歲女性看護工,因血便、腹脹腹痛、體重減輕、虛弱而求診,肛門指診即可摸到腫瘤。大腸鏡檢查約在離肛門緣2公分至10公分處可見腫瘤,表面有潰瘍出血,腸道幾近阻塞,切片檢查證實是小細胞癌。腹部CT檢查顯示,尚未有肝臟或其他器官轉移。因此,接受根治性腹部會陰腫瘤切除術,術後恢復情況尚良好。但不幸術後4個月,發現肝臟及廣泛腹腔轉移而死亡。
Small cell carcinoma of the rectum is very unusual and, although its precise incidence is not clear, it comprises less than 0.2 percent of all colorectal cancers. This tumor exhibits highly aggressive behavior. The treatment of choice is combination chemotherapy similar to that used for small cell cancer of the lung, but in small localized tumors, the combination of surgery plus chemotherapy still has a chance for cure. We present here a case of small cell carcinoma of the lower rectum in a 58-year-old female who visited us because of repeated bloody stool passage with tenesmus noted for more than 2 months. Colonoscopic examination revealed a rectal mass with nearly total luminal obstruction and a biopsy indicated small cell carcinoma. She underwent an en bloc abdomino-perineal resection and had an uneventful recovery, although she died of wide-spread metastasis only 4 months after the operation.