Collagenous ileitis: a study of 13 cases.

Area of Science:

• Gastroenterology
• Gastrointestinal Pathology
• Histopathology

Background:

• Collagenous ileitis (CI) is an uncommon condition characterized by subepithelial collagen deposition in the terminal ileum.
• Existing literature primarily reports CI in association with collagenous colitis (CC) or lymphocytic colitis.

Purpose of the Study:

• To retrospectively analyze the clinicopathological features of collagenous ileitis.
• To investigate the association of CI with other gastrointestinal collagenous diseases.
• To evaluate the clinical course and outcomes of patients with CI.

Main Methods:

• Retrospective review of 13 cases of collagenous ileitis over a 9-year period.
• Analysis of patient demographics, clinical presentation, medication use, and histological findings.
• Examination of biopsies from other gastrointestinal sites (colon, stomach, duodenum) for associated pathologies.

Main Results:

• Thirteen patients (7 female, 6 male; mean age 64 years) were identified, with diarrhea as the primary symptom in 11.
• Two patient groups emerged: CI associated with other GI diseases (n=7) and isolated CI (n=6).
• Associated conditions included collagenous colitis (7/13), collagenous gastritis (4/9), and celiac disease-related duodenal abnormalities (2/10). Subepithelial collagen thickness averaged 32 μm, with villous blunting and increased intraepithelial lymphocytes noted in several cases.

Conclusions:

• Collagenous ileitis frequently coexists with other gastrointestinal collagenous conditions and celiac disease.
• Histological features such as villous blunting and increased intraepithelial lymphocytes are common in CI.
• Resolution of collagen deposition and symptoms was observed in follow-up cases, suggesting a potentially favorable prognosis.