ICD-10 Code C88.3 – Immunoproliferative small intestinal disease (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C88.3 – Immunoproliferative small intestinal disease
What it is
C88.3 identifies immunoproliferative small intestinal disease, a rare lymphoma-like disorder of the small intestine. Use it when documentation names this specific condition or its classic alpha-heavy-chain disease form.
Clinical signs
Clinical features vary; refer to documentation. Standard references describe malabsorption, chronic diarrhea, abdominal pain, and weight loss, often with small-bowel involvement and abnormal lymphoid proliferation.
When to use this code
Use C88.3 when the provider documents immunoproliferative small intestinal disease, including alpha-heavy-chain disease. It may appear in pathology, gastroenterology, or oncology notes describing a primary small-intestinal lymphoproliferative disorder. If the record only says “small bowel lymphoma” or is unclear, check documentation before coding.
Do not use for
Do not use this code for nonspecific enteritis, malabsorption without a confirmed diagnosis, or other gastrointestinal lymphomas not documented as immunoproliferative small intestinal disease. Check documentation.
Coding tip
Code only when the diagnosis is explicitly stated; vague bowel symptoms alone are not enough.