Hepatic portal venous gas and portal venous thrombosis following colonoscopy in a patient with terminal ileal Crohn's disease.

A 27-year-old man developed extensive hepatic portal venous gas (HPVG) shortly after staging colonoscopy for active, ulcerating, terminal ileal Crohn's disease. Non-operative management was instigated with broad-spectrum antibiotics and thromboprophylaxis. Radiology at 72 h demonstrated resolution of HPVG but revealed fresh non-occlusive left portal vein thrombus. Anticoagulation with warfarin was continued for 1 year, during which the thrombus initially progressed and then organised with recanalisation of the portal vein. There were no long-term clinical consequences. HPVG has previously been documented as a rare complication of inflammatory bowel disease and endoscopic intervention. We hypothesise that the barotrauma sustained during endoscopy, in association with active ulceration and mucosal friability, predisposes to the influx of gas and bacteria into the portal system. We describe successful non-operative management of HPVG in this setting and draw attention to an additional complication of portal venous thrombosis, highlighting the importance of thromboprophylaxis and serial radiological examination.

Gastrointestinal polyposis syndromes for the general gastroenterologist.

The occurrence of colonic polyps is a common phenomenon; however, where there are numerous adenomas or other polyps, and/or the patient is at a relatively young age, an inheritable form of gastrointestinal polyposis should be considered. Patients can present via different referral routes, for example, at colonoscopy where multiple polyps are detected, following a personal diagnosis of colorectal cancer, or by family screening. This article outlines the important considerations in the diagnosis of a polyposis syndrome and key diagnostic features to consider. It will also describe the underlying genetic factors associated with the common polyposis syndromes, including classical familial adenomatous polyposis (FAP), attenuated FAP, MUTYH-associated adenomatous polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome and serrated polyposis, and the subsequent management of each condition.

The molecular genetics of colorectal cancer.

Colorectal cancer is a common but heterogeneous disease, which arises through the accumulation of genetic mutations. Knowledge of the molecular basis of colorectal cancer has advanced at a rapid pace in recent years, reflecting progress made in the field of genomic medicine. Targeted therapies have come into mainstream use, and the exciting prospect of treatment regimens tailored to the mutation profile of individual tumours is beginning to emerge. In order to understand the development and application of the next generation of colorectal cancer treatments, it is important that gastroenterologists have a working knowledge of the pathological mechanisms that drive the disease. This review examines our current understanding of the molecular genetics of colorectal carcinogenesis.

A mutation and expression analysis of the oncogene BRAF in pituitary adenomas.

OBJECTIVE: BRAF is an oncogene that is commonly mutated in both melanomas and papillary thyroid carcinomas, usually at position V600E that leads to constitutive activity in the Ras-mitogen-activated protein kinase (MAPK) pathway. We speculated that this same gene may be either mutated at this site, or overexpressed, in pituitary adenomas. DESIGN AND MEASUREMENTS: We sequenced 37 pituitary adenomas for a mutation at the V600E position. In addition, we investigated B-Raf mRNA expression in normal pituitary (n = 5) and nonfunctioning pituitary adenomas (NFPA) (n = 6) by semiquantitative PCR, and in a further 27 pituitary adenomas of various types and 10 normal pituitaries using real-time quantitative PCR. Finally, we explored B-Raf protein expression in 10 normal pituitaries and 12 NFPAs. RESULTS: No sequence mutations for the substitution V600E were identified. B-Raf mRNA was overexpressed in pituitary adenomas compared to normal pituitary, and this was entirely due to overexpression in NFPAs. NFPAs also showed very variable expression of B-Raf protein, but those tumours showing highest levels of B-Raf mRNA expressed the most B-Raf protein. CONCLUSIONS: Mutations previously seen in the majority of melanomas and a substantial minority of papillary thyroid carcinomas are not a frequent finding in pituitary adenomas. However, overexpression of B-Raf mRNA and protein may be a feature of NFPAs, highlighting overactivity of the Ras-B-Raf-MAP kinase pathway in these tumours.