False positive localisation of indium-111 granulocytes in colonic carcinoma

Indium-111 leucocyte scanning has been shown to be a highly accurate technique for detecting abscesses and assessing inflammatory bowel disease. We have encountered two cases of colonic carcinoma which presented as suspected inflammatory bowel disease and were found to localise 111In-labelled granulocytes. Histology revealed an acute inflammatory infiltrate in these tumours. These results indicate that 111In granulocyte scanning has limitations in the diagnosis of inflammatory bowel disease.