Gastrointestinal Tract

Abstract

Cytology samples are obtained by several methods depending on the organ system. In the gastrointestinal system, cytology has proven a useful adjunct to biopsy, allowing for examination of a larger surface area. Moreover, cytology specimens are often the sole samples taken for gastrointestinal pathology. Cytologic material can be obtained by different techniques depending on the location of the lesion; mucosal lesions such as esophagitis are often sampled by brushings and washings while submucosal, gastrointestinal wall, and stenotic lesions are better accessible by fine needle aspiration. However, the interpretation of the pathologic findings and whether the findings on cytological preparations represent lesional material or non-lesional normal tissue, depend on the sampling technique and the location. The involved pathologist should be aware of the clinical presentation and radiologic findings as well as the modality of sampling. It is important to be aware of the cytologic characteristics of the normal components of each section of the gastrointestinal tract to correctly recognize superimposed reactive changes and neoplastic processes. In addition, recognizing contaminants from adjacent organs, foreign body material, and microorganisms is essential in the interpretation of cytology. This chapter is an overview of the normal findings and reactive changes encountered in the cytologic samples obtained from the gastrointestinal tract.