C91.4
ICD-10Non-billable categoryHairy cell leukemia
Official ICD-10-CM descriptor (FY2026)
Hairy cell leukemia
C91.4 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.
Inclusion terms
- Leukemic reticuloendotheliosis
ICD-10-CM FY2026 defines 3 codes beneath C91.4. See the ICD-10-CM index for what this site publishes.
Related codes in C91
- C91.0Acute lymphoblastic leukemia [ALL]category
- C91.1Chronic lymphocytic leukemia of B-cell typecategory
- C91.3Prolymphocytic leukemia of B-cell typecategory
- C91.5Adult T-cell lymphoma/leukemia (HTLV-1-associated)category
- C91.6Prolymphocytic leukemia of T-cell typecategory
- C91.AMature B-cell leukemia Burkitt-typecategory
- C91.ZOther lymphoid leukemiacategory
- C91.9Lymphoid leukemia, unspecifiedcategory
Where this code sits
- Chapter
- 2. Neoplasms (C00-D49)
- Parent code
- C91
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ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.