ICD-10 Code C84.10 – Sézary disease, unspecified site (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.10 – Sézary disease, unspecified site
What it is
C84.10 identifies Sézary disease when the site is not specified. It refers to a cutaneous T-cell lymphoma with malignant T-lymphocytes in the skin and blood.
Clinical signs
Typical findings include widespread red, itchy, scaly skin, lymphadenopathy, and circulating atypical lymphocytes. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents Sézary disease and does not name a specific site. It is appropriate for confirmed Sézary syndrome or disease recorded as unspecified site in the chart. Check documentation if the note uses related lymphoma terms or gives a more specific location.
Do not use for
Do not use it for other cutaneous T-cell lymphomas, mycosis fungoides, or nonspecific dermatitis. If the record does not clearly support Sézary disease, check documentation.
Coding tip
Code only when the diagnosis is explicitly documented; unspecified site does not mean unspecified disease.