Gastrointestinal lymphomas

Malignant lymphomas of the gastrointestinal tract have been the subject of numerous recent studies aimed at defining the radiological appearances of these rare entities, and in particular the non-Hodgkin's lymphomas (NHL). Owing to the submucosal origin of the disease, even deep biopsies performed with state-of-the-art techniques are not always positive. This explains the continued importance of barium studies, especially since therapeutic approaches have evolved. As an example, surgery is no longer the treatment of choice for disease sites in the stomach, the most frequent site of gastrointestinal lymphoma, as many authors now advocate radiotherapy and above all now chemotherapy. Furthermore, computed tomography (CT) and ultrasonography now allow improved evaluation of subdiaphragmatic nodes and the extent of disease within the gastrointestinal tract. The radiological features of gastrointestinal NHL and Hodgkin's disease (HD) warrant differentiation because of the differences in their patterns of anatomical distribution and frequency. Nearly one in every 20 cases of NHL is a primary gastrointestinal site with a favorable prognosis. In contrast to carcinomas, NHL generally does not induce any fibrolastic stroma reaction. The resultant large lesions are readily demonstrated radiologically, and despite the frequent absence of clinical signs, their size suggests the correct diagnosis. Both primary and secondary HD are rare, and in contrast to NHL their prognosis is poor, as they correspond to stage IV disease from the outset. HD is associated with an intense fibrolastic stroma reaction causing moderate-sized focal lesions suggestive of carcinoma