title: Collagenous colitis appeared after 6-year administration of lansoprazole.
abstract: Collagenous colitis (CC) is one of the causes of undefined watery diarrhea, which is histologically accompanied by thickening of the subepithelial collagen layer. CC associated with lansoprazole normally occurs within several weeks after initial administration, but no case presenting after long-term administration of lansoprazole has yet been reported. A 77-year-old male with 6-year history of administration of lansoprazole complained of watery diarrhea and weight loss. Colonoscopy revealed disappearance of vascular networks and red spots in the sigmoid colon. Biopsy specimen showed erosion and collagen bands thickened, so the patient was diagnosed as CC. After lansoprazole discontinuation, the watery diarrhea disappeared and histological abnormalities improved.
authors.affiliation: Department of Internal Medicine, Municipal Nakashibetsu Hospital, Nakashibetsu, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sawada
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan. fjym@asahikawa-med.ac.jp.
authors.forename: Mikihiro
authors.initials: M
authors.lastname: Fujiya
authors.affiliation: Department of Internal Medicine, Municipal Nakashibetsu Hospital, Nakashibetsu, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Itabashi
authors.affiliation: Department of Internal Medicine, Municipal Nakashibetsu Hospital, Nakashibetsu, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Internal Medicine, Municipal Nakashibetsu Hospital, Nakashibetsu, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kubo
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Toshie
authors.initials: T
authors.lastname: Nata
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Ueno
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Inaba
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Moriichi
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Okamoto
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Ikuta
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Tanabe
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Mizukami
authors.affiliation: GLab Pathology Center Co., Ltd., Sapporo, Japan.
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Takagi
authors.affiliation: Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical College, 2-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kohgo
keywords: Collagenous colitis; Lansoprazole; Long-term administration; Microscopic colitis