ICD-10 Code C84.19 – Sézary disease, extranodal and solid organ sites (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.19 – Sézary disease, extranodal and solid organ sites
What it is
C84.19 identifies Sézary disease involving extranodal or solid organ sites. Use it when documentation shows this cutaneous T-cell lymphoma has spread beyond the skin and lymph nodes to another organ.
Clinical signs
Findings may include generalized skin redness, itching, and circulating malignant T cells, with evidence of involvement outside the skin. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents Sézary disease with extranodal or solid organ involvement, such as disease in an internal organ. It may also apply when the record clearly states secondary spread beyond the primary cutaneous site. Check documentation if the involved site is not specified.
Do not use for
Do not use C84.19 for Sézary disease limited to skin or lymph nodes only. Do not substitute it for other cutaneous T-cell lymphomas or for nonspecific lymphoma documentation.
Coding tip
Confirm the exact anatomic site and whether extranodal spread is documented before assigning C84.19.