ICD-10 Code C84.A – Cutaneous T-cell lymphoma, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.A – Cutaneous T-cell lymphoma, unspecified
What it is
C84.A identifies cutaneous T-cell lymphoma when the record does not specify a more exact subtype. It refers to a lymphoma of T-lymphocytes that primarily involves the skin.
Clinical signs
Clinical features vary; refer to documentation. Commonly noted findings include persistent skin lesions such as patches, plaques, or tumors, with possible itching or scaling.
When to use this code
Use this code when the provider documents cutaneous T-cell lymphoma but does not name a specific subtype. It also fits when the chart confirms skin-predominant T-cell lymphoma and the exact variant is not available. If a more specific diagnosis is documented, code that instead.
Do not use for
Do not use it for B-cell lymphomas, other noncutaneous lymphomas, or a fully specified cutaneous T-cell lymphoma subtype. Check documentation if the record names a different lymphoma type.
Coding tip
Query for the exact subtype whenever the note says only “cutaneous T-cell lymphoma.”