Abstract
A 63-year-old woman complained of discomfort in urination and consulted the urology department. Abdominal CT showed a tumor in the rectum, and colonoscopy showed a type 2 tumor at the lower rectum that had a common edge with the dentate line. Biopsy identified small cell carcinoma (neuroendocrine carcinoma) . PET-CT detected a 5-cm lymph node metastasis adjacent to the rectum and also showed inguinal lymph node metastasis. Before the operation, she was treated with chemoradiation therapy. Radiation therapy was targeted the rectum and the left inguinal lymph node, and 40-Gy radiation was used. For chemotherapy, she received CDDP/VP-16 therapy following chemotherapy for lung small cell carcinoma. The tumor shrank significantly and abdominoperitoneal resection was performed. In the resected specimen, the composition of the squamous cell carcinoma was not recognized, but squamous cell carcinoma alone was detected ; however, the effect of chemotherapy was observed. Pathological change from small cell carcinoma to squamous cell carcinoma in the rectum is rare, and we report this case with a review of previously reported cases in the literature.
