ICD-10 Code C84.9A – Mature T/NK-cell lymphomas, unspecified, in remission (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.9A – Mature T/NK-cell lymphomas, unspecified, in remission
What it is
This code identifies a mature T-cell or NK-cell lymphoma that is not further specified and is documented as being in remission. Use it when the record confirms the lymphoma history but shows no active disease.
Clinical signs
Clinical features vary; refer to documentation. In remission, the chart may note absence of active lymphoma findings, with prior diagnosis of mature T/NK-cell lymphoma still relevant to care.
When to use this code
Use this code when the provider documents mature T/NK-cell lymphoma, unspecified, and clearly states remission. It is appropriate for follow-up visits, surveillance, or history-related encounters where the lymphoma remains part of the medical record.
Code it only when the remission status is explicit. If the type is unspecified but the disease is active or the note is unclear, check documentation before assigning C84.9A.
Do not use for
Do not use this code for active lymphoma, relapse, or a different specified T-cell or NK-cell lymphoma. Do not assume remission from treatment history alone; check documentation.
Coding tip
Look for both the lymphoma type and the word “remission” in the provider note before assigning this code.