Elastofibromatous polyp of the sigmoid colon--a case report and review of gastrointestinal elastofibromas.

Elastofibromatous change in the gastrointestinal tract is a rarely reported, usually polypoid lesion of unknown etiology with submucosal stromal change that may mimic amyloid deposition. The constituent amorphous material of the polyp stroma has distinctive features that permit an accurate assessment and diagnosis including: distribution of the material predominantly in the submucosa; distinctive fibrillar and granular appearance of the deposits; thick, irregular, haphazardly arranged bundles of elastic fibres positive for Verhoeff's elastic stain; ultrastructural fibres with an electron dense curvilinear or beaded appearance; lack of amyloid type vascular wall deposits; and lack of amyloid congophilia or crystal violet metachromasia. The clinical, light microscopic, histochemical and ultrastructural characteristics of this deposited material are reviewed in detail in the present report of a patient who presented with an asymptomatic polypoid lesion of the sigmoid colon. Other reported cases are summarized, and their clinical and pathological features are compared with the current case.