Benign gastrointestinal mesenchymal BUMPS: a brief review of some spindle cell polyps with published names.

Context.—There are several benign, predominantly spindle cell, mesenchymal proliferations involving the mucosa and/or submucosa in the gut, which present as polyps and pathologists see as polypectomy specimens. These include perineuriomas, Schwann cell nodules, ganglioneuromas, leiomyomas of the muscularis mucosae, inflammatory fibroid polyps, and granular cell tumors. Objectives.—To evaluate these mesenchymal polyps for their morphologic, immunohistochemical, ultrastructural, and molecular characteristics and to determine some of their associations. Data Sources.—Personal observations based on years of analyzing endoscopic biopsies and a review of the world's literature. Conclusions.—These polyps do surface every so often. There is significant literature covering inflammatory fibroid polyps and granular cell tumors, but there is little literature about the other entities.