C84.A1 Cutaneous T-cell lymphoma, unspecified lymph nodes of head, face, and neck

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from C84 Mature T/NK-cell lymphomas

Excludes1 (never code together)

• personal history of non-Hodgkin lymphoma (Z85.72)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 20 — Lung and Other Severe Cancers
• CMS-HCC V22: HCC 10 — Lymphoma and Other Cancers
• RxHCC V08: HCC 21 — Lymphomas and Other Hematologic Cancers
• ESRD V24: HCC 10

MS-DRG index

Defines the logic of DRG(s) 011-013 in MDC PRE.

Approximate ICD-9-CM (GEMs)

• 202.81 Other malignant lymphomas, lymph nodes of head, face, and neck (approximate)

Code annotations containing back-references to C84.A1

Back-references to C84

• Type 1 Excludes: C26.1 Malignant neoplasm of spleen ("non-Hodgkin lymphoma (C82-C85)")
• Type 1 Excludes: C76 Malignant neoplasm of other and ill-defined sites ("malignant neoplasm of lymphoid, hematopoietic and related tissue (C81-C96)")
• Type 1 Excludes: C77 Secondary and unspecified malignant neoplasm of lymph nodes ("malignant neoplasm of lymph nodes, specified as primary (C81-C86, C88, C96.-)")
• Type 1 Excludes: C82 Follicular lymphoma ("mature T/NK-cell lymphomas (C84.-)")
• Type 1 Excludes: C83.0 Small cell B-cell lymphoma ("mature T/NK-cell lymphomas (C84.-)")
• Type 1 Excludes: C83.3 Diffuse large B-cell lymphoma ("mature T/NK-cell lymphomas (C84.-)")
• Type 1 Excludes: C86 Other specified types of T/NK-cell lymphoma ("mature T/NK-cell lymphomas (C84.-)")
• Code Also: D47.02 Systemic mastocytosis ("non-Hodgkin lymphoma (C82-C85)")
• Code First: Z15.0 Genetic susceptibility to malignant neoplasm (", if applicable, any current malignant neoplasm (C00-C75, C81-C96)")

Nearby codes

• C84.79 Anaplastic large cell lymphoma, ALK-negative, extranodal and solid organ sites
• C84.7A Anaplastic large cell lymphoma, ALK-negative, breast
• C84.7B Anaplastic large cell lymphoma, ALK-negative, in remission
• C84.A Cutaneous T-cell lymphoma, unspecified
• C84.A0 Cutaneous T-cell lymphoma, unspecified, unspecified site
• C84.A1 Cutaneous T-cell lymphoma, unspecified lymph nodes of head, face, and neck (this code)
• C84.A2 Cutaneous T-cell lymphoma, unspecified, intrathoracic lymph nodes
• C84.A3 Cutaneous T-cell lymphoma, unspecified, intra-abdominal lymph nodes
• C84.A4 Cutaneous T-cell lymphoma, unspecified, lymph nodes of axilla and upper limb
• C84.A5 Cutaneous T-cell lymphoma, unspecified, lymph nodes of inguinal region and lower limb
• C84.A6 Cutaneous T-cell lymphoma, unspecified, intrapelvic lymph nodes