Background This an update of the review first published in 2009. Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) administered during the in-hospital period is well-documented, but the optimal duration of prophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominopelvic surgery benefit from prolongation of the prophylaxis up to 28 days after surgery. Objectives To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 14 days after abdominal or pelvic surgery compared with thromboprophylaxis administered during the in-hospital period only in preventing late onset VTE.

Mutations in the human adenomatous polyposis coli (APC) gene are thought to initiate colorectal tumorigenesis. The tumor suppressor function of APC is attributed primarily to its ability to regulate the WNT pathway by targeting the destruction of ␤-catenin. We report here a novel role for APC in regulating degradation of the transcriptional co-repressor C-terminalbinding protein-1 (CtBP1) through a proteasome-dependent process. Further, CtBP1 suppresses the expression of intestinal retinol dehydrogenases, which are required for retinoic acid production and intestinal differentiation. In support of a role for CtBP1 in initiation of colorectal cancer, adenomas taken from individuals with familial adenomatous polyposis contain high levels of CtBP1 protein in comparison with matched, uninvolved tissue. The relationship between APC and CtBP1 is conserved between humans and zebrafish and provides a mechanistic model explaining APC control of intestinal retinoic acid biosynthesis.Germline mutations in the adenomatous polyposis coli (APC) 2,3 tumor suppressor invariably result in familial adenomatous polyposis coli (FAP), a syndrome characterized by early onset colorectal cancer (1). The mechanism by which APC mutations cause colon tumorigenesis is attributed primarily to its role in negatively regulating canonical WNT signaling (2, 3). In this role, APC functions by targeting the transcriptional coactivator ␤-catenin for intracellular degradation through a proteasome-dependent pathway, thereby limiting its ability to associate with T cell factor/lymphoid enhancer factor nuclear transcription factors. Current evidence indicates that following APC mutation, ␤-catenin accumulates and translocates into the nucleus, where it partners with T cell factor/lymphoid enhancer factors to drive a program of cellular proliferation. As evidence for a genetic relationship between APC and WNT signaling, some studies cite the existence of rare, ␤-cateninactivating mutations in colon adenocarcinomas (4, 5). Importantly, however, these mutations do not appear to fully recapitulate the clinical phenotypes associated with APC mutation (6). This discrepancy raises the possibility of additional, ␤-cateninindependent functions for APC.A number of reports suggest that the functions of APC are not limited to its well established role in regulating canonical WNT signaling. For example, APC is reported to bind to microtubules, to regulate asymmetric cell division in Drosophila male germline stem cells, and to promote proper T-cell differentiation in mice (7-11). Further, we recently demonstrated that sporadic human colorectal carcinomas lack retinol dehydrogenases and that introduction of APC into human colon carcinoma cells lines induced the expression of the retinol dehydrogenase DHRS9 in a ␤-catenin-independent manner (12). In addition, apc mcr zebrafish lack expression of intestinal enzymes, such as rdh1l, that are required for retinoic acid production. Injection of apc mcr zebrafish embryos with mRNA encoding rdh1l or treatment with exogenous...

The advantages of LC over OC are the same for the elderly and the young. There may be a selective benefit of laparoscopic left colectomy in the elderly and laparoscopic right colectomy in the young.

Transplant patients develop colorectal cancer at a younger age and exhibit worse five-year survival rates than the general population. These data suggest that chronic immunosuppression results in a more aggressive tumor biology. Frequent posttransplantation colorectal cancer screening program may be warranted.

Patients with IBD had a significantly increased risk for postoperative venous thromboembolism in comparison with patients who had colorectal cancer. Therefore, postdischarge venous thromboembolism prophylaxis recommendations for IBD patients should mirror that for patients who have colorectal cancer. This would suggest a change in clinical practice to extend out-of-hospital prophylaxis for 4 weeks in postoperative IBD patients.

To the Editors:Large lipomas in the left colon are a rare entity, and those that are seen usually have a classic, benign appearance. We describe a patient with a large, left-sided, lipoma that mimicked an adenocarcinoma and produced a partial intussusception as well.A 69-year-old previously healthy man presented with a 1-month history of hematochezia and a 10-lb weight loss. The patient denied any changes in bowel movement frequency; he continued to average 1-2 bowel movements per day. He denied abdominal pain, nausea, or vomiting. Previous medical history included an appendectomy and hernia repair. The patient took no medications and denied any behavioral risk factors. Family history revealed a daughter with ulcerative colitis, and no colorectal cancer.Physical examination was unremarkable. The complete blood count and the basic metabolic panel were normal. Computed tomography (CT) revealed a mass in the descending colon, with partial intussusception involving the sigmoid colon, interpreted as a likely adenocarcinoma. There was no adenopathy or evidence of metastases. Colonoscopy revealed a 7-cm, ulcerated, fungating, mass on a thick stalk, with partial intussusception just distal to the splenic flexure ( Fig. 1). Biopsies of the mass only revealed benign inflammation without malignant tissue.Because of the appearance of the lesion and the negative findings of biopsies, a repeat colonoscopy was performed. After careful evaluation, the lesion was felt to be removable via endoscopic means alone. The lesion was removed with a large snare and electrocautery in a single piece. There were no complications. Pathology revealed a 7-cm inflamed and ulcerated lipoma, with no evidence of malignancy. The patient has done well thereafter.This case demonstrates how, on rare occasions, large colonic lipomas and malignancies can be difficult to differentiate prior to resection. With regards to symptoms and endoscopic appearance, the two can be indistinguishable. Even with abdominal imaging and direct colonoscopic visualization, lipomas can imitate carcinomas.Despite being the third most common benign tumor of the colon, colonic lipomas are comparatively rare [1], with a reported incidence less than 5% [2, 3]. Colonic lipomas are positively correlated with distance from the anus. Unlike that in our patient, almost half are found in the ascending colon [4].Colonic lipomas are most frequently small and asymptomatic [5]. Only one-quarter of all lipomas are symptomatic [6], and those symptomatic lipomas are generally larger than 2 cm, as was the case in our patient. Symptoms can include obstruction, bleeding, or, very rarely, intussusception, as was seen in our patient [2,3].With barium enema, lipomas most often appear as ovoid, well-demarcated, filling defects. By the application of external pressure to the abdomen, or with physiological peristalsis, a ''squeeze-sign''-a change in the appearance of the filling defect-can sometimes be elicited. On CT scan, lipomas also typically appear ovoid, with well-defined margins, and with absor...

Reinforcing the circular staple line in colorectal anastomoses with bioabsorbable material did not significantly affect the anastomotic leak rate but may have reduced anastomotic strictures. Most strictures did not require an anastomotic revision or delay in stoma closure. The bioabsorbable material may positively affect some aspects of the healing of circular stapled colorectal anastomoses; however, additional research on factors associated with anastomotic leakage is needed.

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