C91.50 is the authoritative medical code for Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission. This classification is used in medical billing and clinical recording to specify the clinical criteria for adult t-cell lymphoma/leukemia (htlv-1-associated) not having achieved remission (ICD-10-CM C91.50), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission is a billable ICD-10-CM diagnosis code C91.50. Inclusion terms: Adult T-cell lymphoma/leukemia (HTLV-1-associated) with failed remission; Adult T-cell lymphoma/leukemia (HTLV-1-associated) NOS. Excludes1 (not coded here): personal history of leukemia Z85.6. Excludes2 (not included here): 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.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for C91.50 in the official ICD-10-CM tabular list.
Inclusion Terms
Alternative terms the tabular list files under this code.
- Adult T-cell lymphoma/leukemia (HTLV-1-associated) with failed remission
- Adult T-cell lymphoma/leukemia (HTLV-1-associated) NOS
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- personal history of leukemia Z85.6
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
What can't be coded together with C91.50?
Per Excludes1 instructions, C91.50 must not be reported with: personal history of leukemia (Z85.6).
Can C91.50 be reported alongside related conditions?
Per Excludes2 instructions, C91.50 and the following may both be reported 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).
What conditions are included under C91.50?
Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission includes: Adult T-cell lymphoma/leukemia (HTLV-1-associated) with failed remission; Adult T-cell lymphoma/leukemia (HTLV-1-associated) NOS.
Codes in This Family (36)
Official ICD-10-CM classifications in the same code family as C91.50, with their registry titles.
- C91 — Lymphoid leukemia
- C91.0 — Acute lymphoblastic leukemia [ALL]
- C91.00 — Acute lymphoblastic leukemia not having achieved remission
- C91.01 — Acute lymphoblastic leukemia, in remission
- C91.02 — Acute lymphoblastic leukemia, in relapse
- C91.1 — Chronic lymphocytic leukemia of B-cell type
- C91.10 — Chronic lymphocytic leukemia of B-cell type not having achieved remission
- C91.11 — Chronic lymphocytic leukemia of B-cell type in remission
- C91.12 — Chronic lymphocytic leukemia of B-cell type in relapse
- C91.3 — Prolymphocytic leukemia of B-cell type
- C91.30 — Prolymphocytic leukemia of B-cell type not having achieved remission
- C91.31 — Prolymphocytic leukemia of B-cell type, in remission
- C91.32 — Prolymphocytic leukemia of B-cell type, in relapse
- C91.4 — Hairy cell leukemia
- C91.40 — Hairy cell leukemia not having achieved remission
- C91.41 — Hairy cell leukemia, in remission
- C91.42 — Hairy cell leukemia, in relapse
- C91.5 — Adult T-cell lymphoma/leukemia (HTLV-1-associated)
- C91.51 — Adult T-cell lymphoma/leukemia (HTLV-1-associated), in remission
- C91.52 — Adult T-cell lymphoma/leukemia (HTLV-1-associated), in relapse
- C91.6 — Prolymphocytic leukemia of T-cell type
- C91.60 — Prolymphocytic leukemia of T-cell type not having achieved remission
- C91.61 — Prolymphocytic leukemia of T-cell type, in remission
- C91.62 — Prolymphocytic leukemia of T-cell type, in relapse
- C91.9 — Lymphoid leukemia, unspecified
- C91.90 — Lymphoid leukemia, unspecified not having achieved remission
- C91.91 — Lymphoid leukemia, unspecified, in remission
- C91.92 — Lymphoid leukemia, unspecified, in relapse
- C91.A — Mature B-cell leukemia Burkitt-type
- C91.A0 — Mature B-cell leukemia Burkitt-type not having achieved remission
- C91.A1 — Mature B-cell leukemia Burkitt-type, in remission
- C91.A2 — Mature B-cell leukemia Burkitt-type, in relapse
- C91.Z — Other lymphoid leukemia
- C91.Z0 — Other lymphoid leukemia not having achieved remission
- C91.Z1 — Other lymphoid leukemia, in remission
- C91.Z2 — Other lymphoid leukemia, in relapse
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:
ICD Code C86.50
Angioimmunoblastic T-cell lymphoma not having achieved remission
ICD Code C92.50
Acute myelomonocytic leukemia, not having achieved remission