Indeterminate colitis

A percentage of patients with inflammatory bowel disease cannot be clearly diagnosed with ulcerative colitis or Crohn's disease. This could be the result of an incorrect classification due mostly to the almost universally accepted assumption that there are only two types of inflammatory bowel disease. It is more than likely that there are really many more types of colitis than we now recognize, but this problem of differential diagnosis cannot be solved using serological or histological tests, for example. This session presents the case of a patient who had successive diagnoses of indeterminate colitis, ulcerative colitis and Crohn's disease. The patient was prescribed many different medical treatments and underwent various surgical procedures, with a definitive diagnosis being made at the time of the last operation. Many aspects of indeterminate colitis are discussed and it is emphasized that there may be more types of colitis than are now recognized. Serological markers can be of great help in difficult cases such as indeterminate colitis, although the use of markers such as ANCA and ASCA cannot be used on a routine basis. The lack of conclusive histological criteria in the differentiation between ulcerative colitis and Crohn's disease is also discussed, as well as the growing number of clinicopathological methods that have appeared in the literature and that should be included in the pathological diagnosis. The session also addresses the importance of trying to exhaust the diagnostic possibilities before defining a case as indeterminate colitis, particularly due to problems that can later arise with the prognosis, treatment and disease evolution.