Light micrograph of an appendiceal carcinoid tumour. The tumour cells (darker purple-blue) form small clusters separated by collagenous stroma (pink strands). Carcinoid tumours often occur in the tip of the appendix and can be seen (as was this example) incidentally in an appendix removed for acute appendicitis. Haematoxylin and eosin stained tissue section. Magnification: 200x when printed at 10 centimetres.