Collagenous colitis in a Japanese woman: successful treatment with mesalazine.

mainly includes two diseases: collagenous colitis and lymphocytic colitis. The diagnosis relies on specific microscopic changes seen in colonic mucosal biopsies. Collagenous colitis was first described in 1976 by Lindström and the typical patient is a middle-aged or elderly woman, with the female-to-male ratio approximately 7: 1. Dear Sir, An 80-year-old Japanese woman was admitted to our hospital with a 4-month history of diarrhea and weight loss (she lost 8 kg during this period). Laboratory data were almost normal. Upper and lower endoscopic examination and radiological enteroclysis revealed no specific findings. Biopsies were taken from the colon and rectum. From seven samples, none of them showed cryptitis, crypt abscess, alternation of crypt or hyperplasia. Congo red staining was also negative. All specimens stained with the Masson trichrome method revealed thickening of the subepithelial collagen layer beneath the basal membrane, inflation of the lamina propria and epithelial lesions with intraepithelial lymphocytes ( fig. 1 ). We made a diagnosis of collagenous colitis and mesalazine therapy (1.5 g/day) was started. As the patient was elderly, we did not choose prednisolone treatment. The symptoms resolved 1 week after the procedure. Microscopic colitis is a disease defined as those entities characterized by chronic watery non-bloody diarrhea, abdominal pain, normal radiological and endoscopic appearances and microscopic abnormalities in the colon [1] . Microscopic colitis Published online: June 24, 2008