Coeliac disease and lymphoma.

Following the original description of lymphoma complicating coeliac disease [1], it has become clear that patients with coeliac disease have a 50to a 100-fold increased risk of developing malignant lymphoma compared with the general population [2,3]. The exact risk is unknown as the precise prevalence and incidence of coeliac disease in the population is also unknown. Lymphoma may present in two main ways. First, clinical deterioration may be seen in coeliac patients previously well controlled on a gluten-free diet, or secondly symptoms may develop or longstanding symptoms may worsen, allowing the diagnosis of coeliac disease and lymphoma to be made more or less at the same time [4-7]. The symptoms of coeliac disease and of the complicating lymphoma are so similar initially that the diagnosis of the lymphoma is often made very late with a correspondingly poor prognosis [5,6]. There are four areas of difficulty concerning coeliac lymphoma that will be discussed in this article: do patients presenting with a flat jejunal mucosa and lymphoma have coeliac disease?; what type of lymphoma occurs in coeliac patients?; how can the diagnosis of lymphoma be made earlier?; does a gluten-free diet protect against the development of lymphoma in the coeliac patient?