ICD-10 Code C85.23 – Mediastinal (thymic) large B-cell lymphoma, intra-abdominal lymph nodes (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C85.23 – Mediastinal (thymic) large B-cell lymphoma, intra-abdominal lymph nodes
What it is
This code identifies mediastinal (thymic) large B-cell lymphoma involving intra-abdominal lymph nodes. Use it when documentation specifies this lymphoma subtype and nodal site.
Clinical signs
Clinical features vary; refer to documentation. Commonly, lymphoma may present with lymph node enlargement, systemic “B” symptoms, or imaging findings showing nodal disease.
When to use this code
Use C85.23 when the provider documents mediastinal (thymic) large B-cell lymphoma with involvement of intra-abdominal lymph nodes. It is also appropriate when pathology, imaging, or oncology notes clearly support this exact diagnosis. If the site or subtype is unclear, check documentation before coding.
Do not use for
Do not use this code for other non-Hodgkin lymphomas, unspecified lymphoma, or disease limited to a different lymph node region. Check documentation if the record only says “lymphoma” or “mediastinal mass.”
Coding tip
Code the lymphoma only when both the histology and the nodal site are documented, and verify whether the condition is primary, secondary, or unspecified.