ABSTRACT
A 42-year-old woman gives a 2–3 month history of abdominal pain, diarrhoea and rectal bleeding. She passes blood-stained motions four to six times each day. She has also developed progressive tiredness and loss of appetite. On examination she is pale. There is no lymphadenopathy. She has mild generalised abdominal tenderness, but there is no organomegaly. Her blood count shows
