Histologic evaluation of gastrointestinal biopsies from immunocompromised patients

Immunocompromised patients are at an increased risk for a variety of gastrointestinal illnesses related to infections and therapeutic interventions. The pathologic evaluation of gastrointestinal mucosal biopsies plays a critical role in diagnosing and managing infections, inflammatory conditions, and therapy-related complications in this vulnerable population. The purpose of this review is to discuss the histologic features of selected viral, bacterial, fungal and parasitic infections that show a predilection for immunocompromised hosts or have a propensity to cause more severe disease in these patients. We will also provide a brief overview of the gastrointestinal manifestations associated with selected common primary immunodeficiency diseases and therapy-related immunosuppression. The major differential diagnoses that can complicate clinical management are also discussed.