Beyond the mucosa: unveiling selected mesenchymal lesions of the gastrointestinal tract

Although rare in everyday practice, the gastrointestinal tract is the most common visceral site of mesenchymal neoplasms. The clinical presentation, layer involved and some histological features of these neoplasms in the gastrointestinal system can overlap among each other and can generate challenging diagnostic problems for surgical pathologists. Additionally, misdiagnoses on initial biopsy can result in misguided patient management and preoperative treatment. Herein, we offer a review of the morphologic and immunophenotypic features of selected mesenchymal neoplasms arising from the submucosa, muscularis propria, and mesentery with emphasis on the inherent diagnostic pitfalls and differential diagnoses of these entities to aid surgical pathologists in their accurate recognition which is imperative for patient clinical management, syndromic associations, and treatment.