Malabsorption Work-up: Utility of Small Bowel Biopsy

A wide variety of small intestinal mucosal diseases lead to malabsorption. Although stool studies, especially stool for excess fat, and functional tests for deficiency states are important clues to malabsorption, small intestinal biopsies are probably the most crucial part of the diagnostic process. Many mucosal disorders have distinctive histologic features that allow for precise diagnosis. However, these histologic changes might be subtle. The role of the gastroenterologist is to provide the pathologist with adequate clinical information and tissue material to ensure a complete examination pathologically. Celiac disease is the most common mucosal cause of chronic malabsorption in the western world. Celiac disease can present classically as large volume fatty diarrhea, but it more commonly presents with subtle clinical symptoms or iron deficiency anemia. Although the histologic hallmark of celiac disease is increased intraepithelial lymphocytosis along with villous atrophy, increased intraepithelial lymphocytosis alone in an appropriate clinical context might suggest the diagnosis of celiac disease. The aim of this review is to highlight the importance of close cooperation and communication between the gastroenterologist and the pathologist to optimize the diagnosis of mucosal diseases that result in malabsorption.