Amoebic colitis

Amoebic colitis is caused by the parasite Entamoeba histolytica (E. histolytica). The condition is prevalent in countries with poor sanitation but is increasing within developed countries secondary to global travel and immigration. We report a case of amoebic colitis diagnosed in a patient with a clinical diagnosis of Crohn's disease and with no travel history. Colonic biopsies showed focal active colitis with ulcer slough; deeper levels looking for granulomas fortuitously revealed the amoebae. The diagnosis was confirmed by positive serology and symptomatic improvement after a course of eradication treatment. Pathologists should look for amoebae in biopsies for inflammatory bowel disease (IBD), as endoscopic and histological appearances of IBD and amoebic colitis can be similar but importantly immunosuppressive therapy is contraindicated in amoebic colitis.