Nonpolypous Hamartomas of the Gastrointestinal Tract: An Updated Review on Classification, Denominations, and Clinical Management.

Purpose: To perform the first systematic report about histological subtypes of nonpolypous hamartomas of the gastrointestinal (GI) tract, from esophagus to anal canal. Design: From over 19,000 studies about hamartomas, most of them published as case series or case presentations, we have selected the most representative ones for the GI tract, excluding polyposis syndromes. To have a whole picture of these hamartomas, all of the data were combined with the personal experience of the authors who are GI pathologists. Results: The examined articles showed predominance of vascular and combined vascular and mesenchymal hamartomas. Arteriovenous hamartomas or Brunner gland hamartomas are mainly diagnosed in the small intestine, with preponderance for duodenum. Other malformations such cavernous hamartomas are more specific for the colorectal segments, whereas chondromatous hamartomas or those derived from the neural ectoderm were mostly reported in the esophagus. As newly recognized entities were admitted in the last years, misdiagnosis is frequent, and the best therapeutic approach is far to be known. Conclusion: Even rare, hamartomas of the GI tract need to be differentiated from tumors and familial polyposis syndromes. Knowing their proper denominations and possible complications is valuable for gastroenterologists, pathologists, and surgeons, to be aware in the differential diagnosis.