The significance of mucinous carcinoma has been controversial since first described by Parham in 1923. Previous reports have suggested that mucinous tumors affect young patients, involve the more proximal colon, are more advanced at diagnosis, and have a poorer prognosis than nonmucinous colon carcinoma. More recent reports have refuted these results. In an effort to clarify the significance of mucinous histology, a retrospective review of cases of invasive colon cancer treated at the Ochsner Clinic between 1982 and 1985 was undertaken. Mucinous adenocarcinoma, as defined by > or = 50 percent mucin, was found in 52 patients. During the same period, 343 nonmucinous adenocarcinomas were resected. The mean age, distribution within the colon, stage at diagnosis, and survival of mucinous carcinoma patients were compared with those with nonmucinous tumors. Mucinous tumors presented at a statistically significant more advanced stage (38 percent vs. 22 percent Dukes C lesions; P < 0.01). No significant differences were seen in age at presentation, distribution within the colon, or stage-for-stage survival when the entire group was analyzed. Mucinous carcinomas of the rectum occurred at an advanced stage more frequently (P < 0.05) than nonmucinous rectal carcinomas and had a markedly worse five-year survival (11 percent vs. 57 percent; P < 0.002).

Incidence of hemorrhage after colonoscopic polypectomy or biopsy is low, and in our series, hemorrhage resolved without the need for surgical intervention. Management includes initial stabilization followed by diagnostic evaluation. Technetium-tagged red blood cell nuclear scintigraphy identifies ongoing bleeding and identifies patients in whom additional invasive procedures (arteriography lower gastrointestinal tract endoscopy) are warranted.

Selected patients with colonoscopic perforation may be safely treated nonoperatively. Surgical treatment is reserved for patients with a large perforation or diffuse peritonitis.

Treatment of patients with malignant polyps must be individualized based on evolving criteria. Patients in whom polypectomy margins are inadequate should undergo colectomy. With appropriate selection criteria, patients selected for colectomy had a five-year survival rate similar to the rate of those treated by polypectomy alone.

Patients with immediate blush on 99mTc-labeled red blood cell scintigraphy required urgent angiography. Patients with delayed blush have low angiographic yields. These data suggest that patients with delayed blush or negative scans may be observed and evaluated with colonoscopy.

One hundred seventy patients with gastrointestinal carcinoid tumors were treated at Ochsner Clinic from 1958 to 1990. Ninety-four rectal carcinoid tumors were diagnosed and treated during this time. Carcinoid tumors of the rectum represented the most frequent primary site (55 percent), followed by carcinoids of the ileum (12 percent), appendix (12 percent), colon (6 percent), stomach (6 percent), jejunum (2 percent), pancreas (2 percent), and other (5 percent). One-half of rectal carcinoids were discovered during anorectal examination of asymptomatic patients. The remainder were found primarily by examination of patients for symptoms of benign anorectal conditions. The diagnosis of rectal carcinoid was made at the time of initial examination in 61 patients. This allowed definitive treatment in a single session by local excision and fulguration in 48 patients. The remainder were treated by repeat biopsy and fulguration (25 patients) or by transanal excision (12 patients). Overall, 85 carcinoid tumors of the rectum measuring less than 2 cm were treated by local excision and fulguration or by transanal excision, with an average five-year follow-up. There were no local recurrences. Ten patients with metastasizing rectal carcinoids averaging 4 cm were treated. All were symptomatic at presentation and fared poorly despite radical surgery. Three were alive at three years but only one survived five years. At our institution, rectal carcinoids were the most frequently detected carcinoid tumor. Small carcinoids of the rectum were adequately treated by local excision and fulguration or by transanal excision, with no local recurrence. The true incidence of rectal carcinoids is detected only with careful and complete rectal examination of the asymptomatic screening population by experienced surgeons. With more widespread screening of the well population, rectal carcinoids may become recognized as the most frequent human carcinoid tumor.

Forty-eight cases of Ogilvie's syndrome, colonic pseudo-obstruction, presenting between 1983 and 1989 were retrospectively reviewed to assess the results of colonoscopic decompression and to identify potential etiologic factors. Three patients had spontaneous resolution with medical treatment. Forty-five patients required 60 colonoscopic decompressions: 38 (84 percent) were successfully treated using colonoscopy; five (11 percent) required an operation; and two died within 48 hours of colonoscopy from medical causes. No complications or deaths were the result of colonoscopy. Twenty-nine patients (64 percent) were successfully treated with a single colonoscopy. One-third of patients required serial decompressions. Average cecal diameter in patients with successful colonoscopic decompression was 12.4 cm but was larger for patients requiring more than one colonoscopy (13.3 cm) and for those who failed colonoscopic therapy (13.4 cm). The spine or retroperitoneum had been traumatized or manipulated in 52 percent of patients. Patients with Ogilvie's syndrome were being treated with narcotics (56 percent), H-2 blockers (52 percent), phenothiazines (42 percent), calcium-channel blockers (27 percent), steroids (23 percent), tricyclic antidepressants (15 percent), and epidural analgesics (6 percent) at diagnosis. Electrolyte abnormalities included hypocalcemia (63 percent), hyponatremia (38 percent), hypokalemia (29 percent), hypomagnesemia (21 percent), and hypophosphatemia (19 percent). Colonoscopic decompression in Ogilvie's syndrome is safe and effective management. Multiple pharmacologic and metabolic factors, as well as spinal and retroperitoneal trauma, appear to alter autonomic regulation of colonic function, resulting in colonic pseudo-obstruction.

Perforation of the rectum or sigmoid colon complicated 5 of 2200 barium-enema examinations performed during a 4-year period. Three patients with rectal perforations manifested by air extravasation were successfully treated with intravenous antibiotics and complete bowel rest. Two patients with barium extravasation were treated with immediate operation and colostomy. All five patients recovered. Perforation was found to be associated with a rectal stricture due to ulcerative colitis, a rectal cancer, an incarcerated inguinal hernia, fulminant ulcerative colitis, and a normal colon in an elderly patient. To determine the pressure in the rectum that could potentially be generated during a barium-enema examination, the pressures created by a standard barium delivery set were measured, using 1-meter columns of water, 25 percent diatrizoate sodium (Hypaque), 20 percent barium, and 80 percent barium. The columns generated pressures of 70, 85, 95, and 120 mm Hg respectively. Squeezing the delivery bag increased the pressure 21 to 79 percent or a maximum of 55 mm Hg. Colorectal perforation during barium-enema examination that was not accompanied by barium extravasation could be successfully treated nonoperatively. The associated pathology and our studies of pressures generated during a barium-enema examination allow us to suggest that the incidence of colorectal perforation during barium-enema radiography can be reduced by 1) performing proctoscopy prior to barium enema, 2) avoiding the use of the rectal balloon in patients with known rectal lesions, 3) avoiding barium studies in patients with active colitis, 4) avoiding generation of pressure greater than that created by a column of barium suspension of one meter, and 5) using a lower concentration of barium when possible.