Mesenchymal Lesions Often Presenting as Polyps of the Gastrointestinal Tract

Throughout the gastrointestinal tract, mucosal- and submucosal-based mesenchymal lesions often present as polyps and cause diagnostic challenge. In this chapter, the most commonly encountered mesenchymal polyps are discussed including their clinical and endoscopic features, histologic characteristics, molecular pathogenesis, syndromic association, and the most relevant differential diagnosis. The information is of critical importance to help recognize these lesions and make accurate diagnosis.