Gastrointestinal Tract Perineuriomas and Benign Fibroblastic Polyps: Case Report and Comprehensive Systematic Review.

Background: Perineurioma is a rare benign peripheral nerve sheath tumor that can arise in various body locations. In the gastrointestinal (GI) tract, perineuriomas are uncommon and have only been reported in case reports and case series. In addition, a new classification suggests reclassifying benign fibroblastic polyps as perineurioma when they show positive markers of perineurial differentiation. Objective: This study aims to enhance understanding of GI tract perineuriomas by presenting a new case and conducting a systematic literature review. Methods: We described a new case of colonic perineurioma and systematically reviewed all case reports and case series on GI perineuriomas and benign fibroblastic polyps with perineurial markers. We searched ScienceDirect, PubMed/MEDLINE, and Web of Science up to May 2024. Results: A total of 148 cases were analyzed, and most of the cases were published in the last decade (2014-2024). The majority were females (59.46%), with a mean age of 51 years (standard deviation [SD] ±14.87). Most GI perineuriomas (87.5%) were in the distal colon, predominantly in the sigmoid/rectosigmoid (56%) and rectum (14%). Outside the colon, the stomach was the most affected site (7 of 10 cases), with fewer cases in the small intestine and esophagus. The two most commonly performed stains were for epithelial membrane antigen (EMA) and glucose transporter 1 (GLUT-1), at 75% and 56% of cases, respectively. Noncolonic perineuriomas were generally larger and more symptomatic than colonic ones. Submucosal polyps were more likely symptomatic than mucosal polyps. Conclusion: Perineurioma in the GI tract is a rare benign polyp mainly identified in the distal colon. Its rarity and limited follow-up data restrict our understanding of recurrence rates. We recommend reporting uncommon polyp locations, detailing polyp morphologies, and using at least two markers for classification.