ICD-10 Code C84.A1 – Cutaneous T-cell lymphoma, unspecified lymph nodes of head, face, and neck (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.A1 – Cutaneous T-cell lymphoma, unspecified lymph nodes of head, face, and neck
What it is
This code identifies cutaneous T-cell lymphoma involving the lymph nodes of the head, face, and neck when the node details are not otherwise specified. Use it for documented disease in this anatomic region.
Clinical signs
Clinical features vary; refer to documentation. Findings may include enlarged lymph nodes in the head, face, or neck region, with evidence of cutaneous T-cell lymphoma on the record.
When to use this code
Use this code when the provider documents cutaneous T-cell lymphoma affecting unspecified lymph nodes of the head, face, and neck. It is appropriate when the site is clear, but the record does not name a more specific nodal description.
Code it from the diagnosis statement, pathology report, or specialist note if the documentation supports this exact site and lymphoma type. If the chart gives a more specific nodal or disease description, use that instead.
Do not use for
Do not use this code for cutaneous T-cell lymphoma without lymph node involvement, or for lymph node disease outside the head, face, and neck. Check documentation if the anatomic site is unclear.
Coding tip
Match the exact lymphoma type and nodal location in the provider note before assigning C84.A1.