C84.90
BillableMature T/NK-cell lymphomas, unspecified, unspecified site
HCC Category Mapping
V28HCC 20 — Lung and Other Severe Cancers
0.000V24HCC 10 — Lymphoma and Other Cancers
0.675ESRDHCC 10 — Lymphoma and Other Cancers
0.000RxHCCHCC 21 — Hodgkin Lymphoma and Other Cancers
0.000What This Code Means
A general category for mature T-cell or natural killer cell lymphomas when the specific type cannot be determined and the cancer location is not specified.
Coding Tips
Clinical Significance
Mature T/NK-cell lymphomas, unspecified, unspecified site represents the most general code for T-cell or natural killer cell lymphomas when neither the specific subtype nor the anatomical site can be determined. This code should be used only as a last resort when pathology cannot further classify the lymphoma. Query for additional diagnostic workup whenever possible to enable more specific coding.
Documentation Requirements
- ✓Pathology confirming a mature T-cell or NK-cell lymphoma lineage
- ✓Documentation explaining why a more specific subtype cannot be determined
- ✓Immunophenotyping results showing T-cell or NK-cell markers
- ✓Documentation that additional workup was considered or performed
- ✓Clinical staging if available
Commonly Confused Codes
C84.40 — PTCL-NOS, unspecified site: PTCL-NOS is itself a specific WHO classification category; C84.90 is for truly unclassifiable mature T/NK-cell lymphomasC85.90 — Non-Hodgkin lymphoma, unspecified: Even more general; use only when lineage (B-cell vs. T-cell) cannot be determinedC84.A0 — Cutaneous T-cell lymphoma, unspecified: If skin involvement is documented, consider this more specific codeC84.60/C84.70 — ALCL ALK-positive/negative: If ALCL morphology is identified, use specific codes
Code Hierarchy
└C84Mature T/NK-cell lymphomas└C84.9Mature T/NK-cell lymphomas, unspecified└C84.90Mature T/NK-cell lymphomas, unspecified, unspecified site
└C84.90Mature T/NK-cell lymphomas, unspecified, unspecified site