Neuroendocrine Neoplasm of the Colon and Rectum

PURPOSE: This report outlines the incidence and the clinical features of patients with a neuroendocrine (NE) neoplasm of the colon and rectum and describes, in detail, their histologic and immunohistochemical findings. Also, we attempted to determine the impact of several clinical variables, including tumor stage, tumor location, NE pattern, and cellular subtype on survival. METHOD: Of 690 colorectal cancers operated on from April 1990 to November 1998 at Chungnam National University Hospital, 41 cases were originally diagnosed as poorly differentiated adenocarcinoms on the basis of conventional light microscopy. Paraffin blocks from the aforementioned cases were retrieved, and sections were im munostained with antibodies to human chromogranin A, neuron specific enolase, and synaptophysin. RESULTS: Of the 690 cases of colorectal caner, 35 cases (5.1%) of NE neoplasm were identified retrospectively: 28 males and 7 females. About 90% of the tumors were located at the cecum and the rectosigmoid. Pathologic stages were as follows: modified Dukes stage B2, 6; stage C1, 8; stage D1, 12; and stage D2, 9. The most common metastatic site at the time of diagnosis was the liver (8/9). Four NE patterns were identified: pure NE (n=4), and predominantly NE (n=8), equal NE and exocrine (n=4), and predominantly exocrine (n=19). Two cellular subtypes were identified: well-differentiated (n=3) and intermediate (n=32) cells. Survival statistically correlated with stage (p=0.03), but not with age, sex, tumor location, NE pattern, or cellular subtype. CONCLUSION: This study suggests that NE neoplasms of the colon and rectum are more frequent than previously believed. Since a NE neoplasm is believed to be an extremely biologically aggressive tumor, recognition of a NE neoplasm is very important because of its evident clinical and therapeutic implications.

Primary Resection and Anastomosis of Obstructing Carcinoma of the Left Colon

Differential surgical procedures have been described on the treatment of patients with obstructing carcinoma of the left colon and rectum, and these vary from classical three stage approach to primary resection and anastomosis using intraoperative colonic irrigation or subtotal colectomy. Staged colonic prcedures are associated with significant morbidity and mortality eventhough its initial easy performance, and many patients, unfit for further surgery, are left with a permanent colostomy. We have already reported the initial results of intraoperative antegrade colonic irrigation for one-stage operation in obstructing left colorectal cancers. In this investigation, we evaluated the results of prospective trials of primary resection and anastomosis using intraoperative colon irrigation and subtotal colectomy in obstructing left colon and rectal carcinomas. During recent five years, 19 cases of obstructing left colon and rectal carcinomas which could not received regular colon preparation due to marked abdominal distension were enrolled to this study. There were 12 men and 7 women, and mean age was 61. 14 of the 19 patients which tumors located below mid-descending colon were subjected to primary resection and anastomosis using intraoperative antegrade colonic irrigation, 4 patients which tumors located above the mid-descending colon were treated with subtotal colectomy, and remaining one patient which tumor located upper rectum was performed subtotal coloectomy because of underlying colonic ischemia. There was no mortality and significant postoperative complications such as anastomotic lealrage, pelvic abscess or intraabdominal sepsis which seemed to be related with anastomotic dehiscence. Therefore, primary resection and anastomosis using intraoperative colonic irrigation or subtotal colectomy depending on tumor locations in cases of obstructing left colon and rectal carcinomas might be useful methods to obtain safe one-stage restorative colorectal resections.