C84.1 ICD-10-CM Code: Sézary disease
Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.
Code Set: Valid FY2026 and FY2027. FY2026 took effect October 1, 2025.
Official Registry Overview & Definition
Sézary disease is a non-billable ICD-10-CM category code (C84.1). A more specific billable subcode must be selected for claims submission.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for C84.1 in the official ICD-10-CM tabular list.
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- personal history of non-Hodgkin lymphoma (Z85.72)
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- Kaposi's sarcoma of lymph nodes (C46.3)
- secondary and unspecified neoplasm of lymph nodes (C77.-)
- secondary neoplasm of bone marrow (C79.52)
- secondary neoplasm of spleen (C78.89)
Frequently Asked Questions (FAQ) & Clinical Guidance
Can C84.1 be billed directly?
No. C84.1 (Sézary disease) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Nearest Codes in This Family
Official ICD-10-CM classifications closest to C84.1 in its code family, with their registry titles.
- C84.06 — Mycosis fungoides, intrapelvic lymph nodes
- C84.07 — Mycosis fungoides, spleen
- C84.08 — Mycosis fungoides, lymph nodes of multiple sites
- C84.09 — Mycosis fungoides, extranodal and solid organ sites
- C84.0A — Mycosis fungoides, in remission
- C84.10 — Sézary disease, unspecified site
- C84.11 — Sézary disease, lymph nodes of head, face, and neck
- C84.12 — Sézary disease, intrathoracic lymph nodes
- C84.13 — Sézary disease, intra-abdominal lymph nodes
- C84.14 — Sézary disease, lymph nodes of axilla and upper limb