Pitfalls and errors in the diagnosis of collagenous and lymphocytic colitis.

The diagnosis of both CC and LC is based on a compatible clinical picture and well-established objective histological criteria. The motivation degree of the involved physicians is essential in the diagnosis of microscopic colitis. The gastroenterologist should refer every patient with chronic watery diarrhea to perform a colonoscopy in spite of the benign course of the disease and the absence of alarm symptoms or signs. The endoscopist should take multiple stepwise biopsy samples of the colonic mucosa despite that the mucosa looked macroscopically normal. Finally, the pathologist should be motivated to use objective histological criteria to make the diagnosis. In this context, it is important to define the terminology as clearly as possible to avoid confusion.