ICD-10 Code C84.A4 – Cutaneous T-cell lymphoma, unspecified, lymph nodes of axilla and upper limb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.A4 – Cutaneous T-cell lymphoma, unspecified, lymph nodes of axilla and upper limb
What it is
This code identifies cutaneous T-cell lymphoma, unspecified type, with involvement of lymph nodes in the axilla or upper limb. Use it when the record documents skin-based T-cell lymphoma and regional nodal spread in that anatomic area.
Clinical signs
Findings may include persistent skin plaques, patches, or tumors with enlarged axillary or upper-limb lymph nodes. Clinical features vary; refer to documentation for the confirmed lymphoma subtype and nodal involvement.
When to use this code
Use C84.A4 when the provider documents cutaneous T-cell lymphoma without a more specific subtype and specifically notes lymph node involvement in the axilla or upper limb. Apply it when that nodal region is part of the confirmed diagnosis, not just a suspected finding.
If the chart names a different nodal region or a more specific lymphoma type, code that documented condition instead. Check documentation when the site of nodal involvement is unclear.
Do not use for
Do not use this code for cutaneous T-cell lymphoma without documented axillary or upper-limb lymph node involvement. Do not use it for other lymphoma types or for uncertain lymphadenopathy alone.
Coding tip
Verify both the cutaneous T-cell lymphoma diagnosis and the exact nodal site before assigning C84.A4.