ABSTRACT
Collagenous colitis (CC) has been looked upon as a rare disease in the past years. However, as we have acquired more knowledge about this disease, the cases diagnosed as CC are on the rise. Many case reports on Lansoprazole (LPZ) are available in our country, and our hospital has had three cases in the last year. Here, we present a typical example. Case 1: An 84-year-old woman who had been taking LPZ visited our outpatient clinic, complaining of chronic watery diarrhea for three months. Colonoscopy produced no abnormal findings other than a tiny capillary vascular growth in the descending colon. However, the histopathological findings secured from the entire colonic region revealed a thickened subepithelial collagen band. She was therefore diagnosed as suffering from CC. With the administration of LPZ suspended, her diarrhea improved in two weeks. The other two cases also underwent colonoscopy to check their chronic diarrhea. Their symptoms improved in a few weeks with the intake of LPZ suspended. In the differential diagnosis of chronic diarrhea, therefore, we believe it important to take possible CC into account, review the detailed history of medicine, and perform colonoscopy and mucosal biopsy.