http://72.14.203.104/search?q=cache:fOn ... clnk&cd=10Intraepithelial Lymphocytosis in Architecturally Preserved Proximal Small Intestinal Mucosa: An Increasing Diagnostic Problem With a Wide Differential Diagnosis
Context.-An increased intraepithelial lymphocyte density in an architecturally normal proximal small intestinal mucosal biopsy is a common finding facing surgical pathologists dealing with gastrointestinal biopsy specimens. Approximately 1% to 2% of all proximal small intestinal biopsies will show this change. It is increasingly recognized by surgical pathologists that gluten- sensitive enteropathy is an important cause of this pattern; however, gluten-sensitive enteropathy accounts for the minority of all cases. A wide variety of immunologic stimuli can raise intraepithelial lymphocyte numbers. Among the other common associations are enteric infection, autoimmune disease, drugs, and gastric Helicobacter infection.
Objective.-To outline the causes of intraepithelial lymphocytosis, to highlight the importance and the difficulties faced in establishing gluten-sensitive enteropathy as the cause, and to aid the surgical pathologist in the routine sign out of these cases.
Data Sources.-A review of the literature detailing the causes or associations of proximal small intestinal intraepithelial lymphocytosis is presented.
Conclusions.-Increased lymphocyte numbers in the epithelium of architecturally preserved proximal small intestinal biopsies is a morphologic feature associated with a broad differential diagnosis.
CONCLUSION
Up to 2.5% of proximal small intestinal mucosal biopsies display increased IELs (>25 IELs per 100 epithelial cells) in the absence of villus architectural change. In most cases this is due to immunologic activation of the lymphocytes that are normally resident in the epithelium. The causes for this increase in numbers of IELs are multiple and include reactions to intraluminal antigens and small intestinal manifestations of autoimmune or other allied diseases (see Table). Gluten sensitivity is a common cause, accounting for 9% to 40% of cases.9,10,18 Other common associations include gastric H. pylori infection, a drug reaction, and autoimmune lymphocyte stimulation. In a significant number of cases, a cause is never established. It is the practice of one of us (I.B.) to add a comment to the surgical pathology report in cases in which intraepithelial lymphocytosis is the diagnosis. This comment states "the finding of intraepithelial lymphocytosis with preserved villus architecture is a non specific immunological phenomenon that has a large number of possible causes. A mild histological manifestation of gluten sensitivity is one of these causes. Unfortunately, celiac serology may be negative even in patients that subsequently prove to be gluten sensitive. Other common causes of this appearance include infective enteritis, H. pylori infection, a drug effect eg NSAIDs, and autoimmune disease. In many cases a specific cause is not identified."
Causes of Proximal Small Intestinal Intraepithelial Lymphocytosis With Normal Villus Architecture*
The establishment of a diagnosis of gluten sensitivity can be clinically difficult and relies on a weighted assessment of clinical, serologic, and histopathologic data. Surgical pathologists can help by highlighting cases that have a uniform distribution of IELs over the villus length rather than those showing increased numbers but in a persisting decrescendo pattern because the latter is an unusual feature for GSE.
Awareness of the various conditions associated with increased IELs in architecturally preserved proximal small intestinal mucosa is important to guide the clinician toward a correct diagnosis.
Love,
Joanna
