Clinical significance of colonic intraepithelial lymphocytosis in a pediatric population.

The significance of colonic intraepithelial lymphocytosis has been well described in adults, and is associated with lymphocytic colitis, untreated celiac disease, and medications, among others. Little is known about the meaning of colonic intraepithelial lymphocytosis in the pediatric population; this study examines this finding in a cohort of children. Twenty patients in whom colonic intraepithelial lymphocytosis was a prominent feature were identified from 1999 to 2005. Colonic intraepithelial lymphocytosis was defined as 20 or more intraepithelial lymphocytes per 100 colonocytes present in at least one colonic mucosal biopsy. Each biopsy was examined for numbers of intraepithelial lymphocytes per 100 surface and crypt colonocytes; various architectural, inflammatory, and metaplastic changes were also noted. When available, concurrent duodenal and/or ileal biopsies were examined. Studied clinical parameters included indications for biopsy, clinical follow-up, final diagnosis, comorbidities, autoimmune serologies, and medications. A total of 121 colonic mucosal biopsies were examined in 20 patients who ranged from 1 to 17 years (mean 10.2 years; 40% male). Common indications for endoscopy included diarrhea and abdominal pain. A mean of 29 (+/-22) intraepithelial lymphocytes per 100 enterocytes were seen. Seven patients had colonic intraepithelial lymphocytosis as the only histologic finding. The remaining 13 patients had additional architectural, inflammatory, and metaplastic changes. The mean follow-up period was 14 months (range 1-48 months). Inflammatory bowel disease was diagnosed in 4 of 20 patients and was seen chiefly in biopsies in which colonic intraepithelial lymphocytosis was associated with architectural or inflammatory changes. Common disease associations include celiac disease, lymphocytic colitis, and autoimmune enteropathy. Pediatric colonic intraepithelial lymphocytosis, in the absence of other histologic findings, is associated with various diseases, including celiac disease, lymphocytic colitis, and autoimmune enteropathy. Colonic intraepithelial lymphocytosis in the presence of other inflammatory changes indicates the possibility of idiopathic inflammatory bowel disease. These findings are similar to those seen in adults, with the exception of autoimmune enteropathy.