ICD-10 Code C82.4 – Follicular lymphoma grade IIIb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C82.4 – Follicular lymphoma grade IIIb
What it is
C82.4 identifies follicular lymphoma grade IIIb, a high-grade subtype of follicular lymphoma. It is used when pathology confirms this specific lymphoma grade and not a different non-Hodgkin lymphoma type.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include enlarged lymph nodes, biopsy-proven follicular lymphoma, and histology showing predominantly centroblasts with a diffuse pattern in grade IIIb.
When to use this code
Use this code when the pathology report or oncology documentation specifically states follicular lymphoma grade IIIb. It is appropriate for confirmed diagnoses on biopsy, excision, or other definitive tissue sampling. If the record only says follicular lymphoma without grade, check documentation.
Do not use for
Do not use C82.4 for other follicular lymphoma grades, diffuse large B-cell lymphoma, or unspecified non-Hodgkin lymphoma. If the grade is not documented, do not assume grade IIIb.
Coding tip
Code only after you verify the exact histologic grade in the pathology report or provider note.