Poorly differentiated neuroendocrine cell carcinoma of the rectum: report of a case and literal review.

A 56-year-old man was admitted to our hospital because of anal bleeding. Colonoscopy and barium enema revealed type 4 tumor in the rectum. Biopsy revealed poorly differentiated adenocarcinoma. Low anterior resection with total mesorectal excision and lymph node dissection was performed. In immunohistochemical staining, chromogranin A and synaptophysin were positive at major lesion, and CEA were focal positive. The resected tumor was diagnosed pathologically as neuroendocrine cell carcinoma. The Ki-67 labeling index (LI) was 87.8%, so proliferative activity and potential malignancy was very high. Multiple metastatic tumors appeared in pelvis and lung eight months after operation. Treatment for neuroendocrine cell carcinoma of the rectum was controversial. Surgical resection and adjuvant chemotherapy might be one of the methods for gastrointestinal neruroendocrine cell carcinoma.