The Association Between Primary Sclerosing Cholangitis and Microscopic Colitis: A Systematic Review.

The association between primary sclerosing cholangitis (PSC) and microscopic colitis (MC) has been explored in limited studies, suggesting potential shared pathophysiological mechanisms. This systematic review aimed to investigate this relationship by analyzing studies identified through comprehensive searches in PubMed, Embase, and the Cochrane Library. Two studies met the inclusion criteria: a case series of 12 patients and a case report, collectively analyzing 13 cases. The case series revealed that 75% of MC diagnoses occurred after PSC, with many cases being asymptomatic, suggesting potential underdiagnosis. The case report described a patient with collagenous colitis who developed severe PSC complications, underscoring the bidirectional relationship and clinical impact of these conditions. Both studies highlighted immune dysregulation, genetic predisposition (HLA-DR3, HLA-DRw52a), and alterations in gut flora as shared mechanisms. These findings emphasize the importance of increased clinical vigilance, early diagnosis, and management of MC in PSC patients. Further research is needed to validate these associations, evaluate routine screening, and explore therapeutic approaches.