Endoscopic and Histopathologic Findings of Rituximab-Associated Colitis in a Patient With Scleroderma

Area of Science:

• Immunology
• Gastroenterology
• Oncology

Background:

• Rituximab, a chimeric monoclonal antibody targeting CD20+ B lymphocytes, treats hematologic malignancies and autoimmune diseases.
• While generally safe, rituximab use is associated with gastrointestinal adverse effects, including colitis.
• A rare but documented complication is de novo inflammatory bowel disease development, even without prior digestive history.

Observation:

• A patient with systemic sclerosis on chronic rituximab therapy developed de novo colitis.
• Clinical, endoscopic, and histopathological findings were consistent with ulcerative colitis.

Findings:

• The development of de novo inflammatory bowel disease, particularly ulcerative colitis, is an uncommon but documented adverse effect of rituximab therapy.
• Diagnosis can be challenging due to subtle or overlapping symptoms with other autoimmune conditions.

Implications:

• Clinicians must maintain vigilance for persistent gastrointestinal symptoms in patients receiving anti-CD20 therapy.
• Early endoscopic evaluation and biopsies are essential for timely diagnosis and management of rituximab-induced colitis to prevent complications.