Collagenous colitis and lymphocytic colitis: clinical and endoscopic findings

collagenous colitis (CC) and lymphocytic colitis (LC) are two entities of unknown cause, characterized by chronic watery diarrhea, grossly normal-appearing colonic mucosa and abnormal histopathological findings in colonic biopsies. The clinical features of the disease are based mainly on case reports or small uncontrolled series. Although normal colonoscopic findings are, as a rule, part of the diagnosis of CC, several cases of macroscopic colitis associated with CC have been reported, and the spectrum of endoscopic mucosal changes has not been described in large series.

we present a retrospective study of all patients who underwent total colonoscopy and mucosal biopsy in our Endoscopy Unit between 1991 and 1997. Clinical and endoscopic findings in patients diagnosed as having CC or LC were recorded.

of 676 patients studied, 398 suffered from chronic diarrhea. Collagenous colitis was diagnosed in 22 patients and LC in 10. Eleven per cent of the patients with CC and 20% of those with LC did not have diarrhea. Macroscopic colitis was observed in 6 out of 22 patients with CC (27%) and in 4 out of 10 with LC (40%). Macroscopic lesions included edema, erythema, abnormal vascular pattern, superficial erosions or ulcerations and hemorrhagic lacerations. In this series 7.03% of the patients with chronic diarrhea were diagnosed as having CC or LC.

collagenous colitis and LC are two entities that should be considered in the differential diagnosis of chronic diarrhea. Total colonoscopy with multiple biopsies that include the right colon are mandatory. The presence of macroscopic lesions on endoscopy does not rule out a diagnosis of either entity. We identified patients who fulfilled the histopathological criteria for CC or LC but who did not have diarrhea.