ICD-10 Code C82.03 – Follicular lymphoma grade I, intra-abdominal lymph nodes (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C82.03 – Follicular lymphoma grade I, intra-abdominal lymph nodes
What it is
This code identifies grade I follicular lymphoma involving intra-abdominal lymph nodes. Use it when documentation specifies both the low-grade follicular lymphoma subtype and the abdominal nodal site.
Clinical signs
Clinical features vary; refer to documentation. Follicular lymphoma is often an indolent, painless lymph node malignancy, and intra-abdominal involvement may be found on imaging or biopsy rather than symptoms alone.
When to use this code
Use C82.03 when the provider documents grade I follicular lymphoma in intra-abdominal lymph nodes, such as mesenteric, retroperitoneal, or other abdominal nodal disease. Code it from the confirmed diagnosis, pathology, or oncology note. If the grade or nodal site is not specified, check documentation.
Do not use for
Do not use this code for other lymphoma subtypes, higher-grade follicular lymphoma, or follicular lymphoma in non-abdominal nodes. If the record only says “lymphoma” or gives an uncertain site, do not assume C82.03.
Coding tip
Confirm both the histologic grade and the intra-abdominal node site before assigning this code.