Acute Presentations of GI Neoplasms

Colorectal cancer

Appendicitis from mass effect. There is often eccentric wall thickening of the bowel affected by malignancy.

Bowel perforation may occur secondary to bowel obstruction or bowel wall necrosis from the tumour. Patients are at higher risk if they've undergone radiation or chemotherapy.

Anal cancer

Abcess

Meckel's diverticulum cancer

Meckel's diverticulitis most typically associated with a carcinoid. More rarely it can cause intestinal obstruction and hemorrhage.

Pancreatic cancer

Pancreatitis typically due to pancreatic duct obstruction. The double duct sign may be present. Note that MR or multiphase CT may be needed to differentiate an underlying mass for masslike thickening from pancreatitis.

Gall bladder carcinoma

Cholecystitis, often with a mass replacing the normal gall bladder lumen. In gall bladder carcinoma cholecystitis patients the thickening is more likely to be focal and more prominent as compared to those without cancer.