The Diagnosis of Rare and Problematic Gastrointestinal Tract Infections: An Approach to a Road Less Traveled.

The histopathologist is an integral part of the specialty team involved in the diagnosis of rare and problematic gastrointestinal tract infections. Frequently, routine hematoxylin and eosin morphology, supported by various histochemical and immunoperoxidase stains, enables the rapid diagnosis of such infections. The recent advent of molecular technologies has further augmented the histopathologist's armamentarium. The role of various methodologies that can be applied in the workup of these cases, including those in the immunocompromised individual, is discussed and interpretation in the context of relevant clinical and microbiologic investigation findings, is highlighted.