Benign Fibroblastic Polyp/Perineurioma Elizabeth A. Montgomery, MD Key Facts Terminology Colonic mucosal proliferation of monomorphic spindle cells leading to separation, entrapment, and disorganization of colonic crypts Morphologically identical lesions variably…

Entamoeba Histolytica Laura W. Lamps, MD Key Facts Etiology/Pathogenesis Affects approximately 10% of world population Clinical Issues Nondysenteric infection: Milder symptoms Dysenteric or invasive infection: Sudden, severe diarrhea, abdominal cramps…

Spirochetosis Laura W. Lamps, MD Key Facts Clinical Issues Most commonly affects colonic mucosa in men with HIV/AIDS Most common symptom is diarrhea, but unclear whether spirochetosis actually causes symptoms…

Clostridium Difficile Laura W. Lamps, MD Key Facts Terminology Infection by Clostridium difficile, most common nosocomial GI infection Causes colitis, most often pseudomembranous colitis Etiology/Pathogenesis Usually associated with recent antibiotic…

Enterohemorrhagic E. coli Infections Laura W. Lamps, MD Key Facts Terminology Most common strain of EHEC is O157:H7, but there are others Etiology/Pathogenesis Infection usually acquired from contaminated food Clinical…

Crohn Disease Alexandros D. Polydorides, MD, PhD Key Facts Terminology IBD discontinuously involving upper or lower GI Etiology/Pathogenesis Environmental trigger in genetically predisposed individuals leads to immunologically mediated injury Clinical…

Salmonella Laura W. Lamps, MD Key Facts Terminology Transmitted through contaminated food and water Generally divided into 2 groups: Typhoid and nontyphoid species Clinical Issues Fever Abdominal pain Diarrhea Macroscopic…

Pneumatosis Coli Sharon K. Bihlmeyer, MD Key Facts Terminology Synonym: Pneumatosis cystoides intestinalis Presence of gas in bowel wall Clinical sign of underlying disease process rather than disease entity itself…

Campylobacter Laura W. Lamps, MD Key Facts Terminology Most common stool isolate in United States Clinical Issues Diarrhea Abdominal pain Infants, children, and young adults most commonly affected Higher incidence…

Diverticular Disease-related Colitis Sharon K. Bihlmeyer, MD Key Facts Terminology Ulcerative colitis-like variant (chronic segmental colitis in distribution of diverticula) Crohn-like variant (Crohn-like reaction to diverticulitis in resection specimen) Clinical…