C84.A0
BillableCutaneous T-cell lymphoma, 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 cancer of T cells that primarily affects the skin, but the specific location of affected lymph nodes is not specified.
Coding Tips
- •This is the default code when cutaneous T-cell lymphoma is present but lymph node location is unknown or unspecified
- •If lymph node involvement location is documented, use a more specific C84.A1-A7 code instead
Clinical Significance
Cutaneous T-cell lymphoma, unspecified, unspecified site is a general code for T-cell lymphomas that primarily involve the skin when neither the specific subtype (mycosis fungoides, Sezary syndrome, etc.) nor the lymph node involvement site is specified. Cutaneous T-cell lymphomas are a distinct group from nodal T-cell lymphomas, with different natural histories and treatment approaches. This code should prompt efforts to classify the specific cutaneous subtype.
Documentation Requirements
- ✓Skin biopsy confirming T-cell lymphoma with cutaneous tropism
- ✓Immunophenotyping showing T-cell markers with skin involvement pattern
- ✓Documentation explaining why specific subtype (mycosis fungoides, Sezary syndrome) cannot be determined
- ✓Skin examination findings (patches, plaques, tumors, erythroderma)
- ✓Staging using TNMB system specific to cutaneous lymphoma
Commonly Confused Codes
C84.00 — Mycosis fungoides, unspecified site: The most common cutaneous T-cell lymphoma; use when specifically diagnosedC84.10 — Sezary syndrome: Leukemic variant of cutaneous T-cell lymphoma with erythroderma and circulating Sezary cellsC84.90 — Mature T/NK-cell lymphoma, unspecified: General T/NK lymphoma code without cutaneous specificationL41.0 — Pityriasis lichenoides et varioliformis acuta: Reactive skin condition that can mimic cutaneous T-cell lymphoma
Code Hierarchy
└C84Mature T/NK-cell lymphomas└C84.ACutaneous T-cell lymphoma, unspecified└C84.A0Cutaneous T-cell lymphoma, unspecified, unspecified site
└C84.A0Cutaneous T-cell lymphoma, unspecified, unspecified site