Context: The pathologist plays the leading role in distinguishing pseudoneoplasms from truly neoplastic lesions in the gastrointestinal tract.
Objective: This review was conducted to heighten awareness of pseudoneoplasms, to help differentiate among the various types of pseudoneoplasms, and to help distinguish pseudoneoplasms from malignancies.
Data sources: This review is based on the medical literature on pseudoneoplasms in MEDLINE and the authors' own experiences. Reference lists of retrieved articles were also reviewed to identify additional articles.
Conclusions: A classification of pseudoneoplasms, according to the mechanism of injury to the gastrointestinal tract, morphologic patterns, and heterotopia, may be useful in providing a diagnostic framework in which ancillary techniques often have a diagnostic role. Several pseudoneoplasms may be closely associated with true neoplasms (eg, malakoplakia, prolapsetype lesions) because of the nonspecific nature of the response of the intestine to injury.