Elsevier

Human Pathology

Volume 20, Issue 1, January 1989, Pages 18-28
Human Pathology

Original contribution
Lymphocytic (“microscopic”) colitis: A comparative histopathologic study with particular reference to collagenous colitis

https://doi.org/10.1016/0046-8177(89)90198-6Get rights and content
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Abstract

Lymphocytic colitis, previously termed “microscopic colitis”, is a clinicopathologic syndrome of watery diarrhea, grossly normal colonoscopy, and mucosal inflammatory changes. Since lymphocytic colitis is a new, incompletely characterized entity, a histopathologic study was performed to compare lymphocytic colitis (n = 16), collagenous colitis (n = 17), idiopathic inflammatory bowel disease (n = 16), acute colitis (n = 16), and histologically normal colon (n = 12). The study was a blinded semiquantitative analysis of histologic features in the surface epithelium, lamina propria, and crypts. The most distinctive feature of lymphocytic colitis was increased intraepithelial lymphocytes, particularly in the surface epithelium (P = .0001 v idiopathic inflammatory bowel disease, acute colitis, and normal colon). Other prominent features of lymphocytic colitis included surface epithelial damage (P < .005 v diopathic inflammatory bowel disease and normal colon), increased lamina propria chronic inflammation (P < .01 v normal), and minimal crypt distortion or active cryptitis. There were striking similarities between lymphocytic colitis and collagenous colitis, but subepithelial collagen thickening was seen only in collagenous colitis. Idiopathic inflammatory bowel disease showed prominent crypt distortion and greater active inflammation, in addition to minimal intraepithelial lymphocytes. Acute colitis occasionally demonstrated prominent surface epithelial damage, but was otherwise dissimilar from lymphocytic colitis. We reached the following conclusions: (1) the entity “microscopic colitis” shows characteristic histopathology including prominent lymphocytic infiltration of epithelium, and thus, a more appropriate designation is lymphocytic colitis; (2) although lymphocytic colitis closely resembles collagenous colitis, each entity is distinct on biopsy; and (3) lymphocytic colitis is readily distinguishable from idiopathic inflammatory bowel disease, acute forms of colitis, and normal colorectum.

Keywords

lymphocytic (“microscopic”) colitis
collagenous colitis

Cited by (0)

Supported in part by the National Foundation for Ileitis and Colitis, the The Harvey M. and Lyn P. Meyerhoff Digestive Disease-Inflammatory Bowel Disease Center, and an Institutional Research Grant from The Johns Hopkins University School of Medicine. Dr Lazenby is the recipient of a Fellowship from the National Foundation for Ileitis and Colitis.

Presented in part at the meeting of the United States and Canadian Academy of Pathology (IAP), Chicago, March 1987; and at the National Foundation for Ileitis and Colitis seminar, Ft Lauderdale, FL, October 1987.