Are Collagenous Colitis and Lymphocytic Colitis Distinct Syndromes?

Abstract

The term microscopic colitis has largely evolved to be an umbrella term which includes the histopathological entities of lymphocytic colitis and collagenous colitis. The purpose of this review is to compare these two syndromes. Lymphocytic colitis and collagenous colitis are characterized by chronic watery diarrhea, normal radiographic and endoscopic findings, and abnormal colonic mucosa on biopsy with lymphocytic infiltration of the lamina propria but minimal crypt distortion. Collagenous colitis is further characterized by a thickened subepithelial collagen band. Lymphocytic colitis has an equal sex distribution, while collagenous colitis has a marked female predominance. Histocompatibility phenotypes are also dissimilar. These findings suggest that lymphocytic colitis and collagenous colitis may be related but distinct syndromes.

The epidemiology of microscopic colitis: a 10-year pathology-based nationwide Danish cohort study

“…MC comprises two main subtypes: lymphocytic colitis (LC) and collagenous colitis (CC). The two subtypes share histopathological features characterized by a marked increase in intraepithelial lymphocytes; CC is further characterized by the presence of a thickened subepithelial collagen band [2]. Although LC and CC share histological features, they are considered two related but separate entities.…”

Quantitative Assessment of the Subepithelial Collagen Band Does Not Increase the Accuracy of Diagnosis of Collagenous Colitis

“…Despite the fact that the thickness of the subepithelial amorphous band is the most important single parameter for the diagnosis of CC, there is no consensus among pathologists as to how thick the CC band should be. The various thicknesses of the collagenous band required for a diagnosis of CC include the following: 7 µm or more [8][9][10][11][12][13] ; 10 µm or more [14][15][16] ; thicker, 17 exceeding 18 or at least 19 10 µm; 10 to 15 µm 20 ; 12 µm or more 21 ; and more than 15 µm. 22 Other authors postulated that "any abnormal increase in the subepithelial collagen in the proper inflammatory background should be considered as diagnostic of collagen colitis" 4 and others that the thickness of the band should be the equivalent to the thickness of two RBCs.…”

Lymphocytic colitis presenting as difficult diarrhoea in an African woman: a case report and review of the literature

“…Earlier, Lindstrom had described CC [11]. Some, however, view the two as related but distinct syndromes [12]. LC and CC are relatively rare conditions diagnosed when a patient with chronic, watery and non-bloody diarrhoea has an endoscopically or radiographically normal colon, but colonic biopsies show unique inflammatory changes.…”