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C84.73 ICD-10-CM Code: Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes

C84.73 maps to CMS-HCC V28 19. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupC84.73

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)

C84.73

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes

A type of aggressive lymphoma (cancer of immune cells) without a specific genetic marker (ALK-negative) that is located in the lymph nodes within the abdominal cavity.

Buddy the Bee presenting code insight

Buddy Insight

Anaplastic large cell lymphoma, ALK-negative, involving intra-abdominal lymph nodes indicates aggressive T-cell lymphoma without the ALK marker affecting abdominal nodal basins.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 19

Coefficient HCC 19: 1.798 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 010

Code-level coefficient reference

ESRD/PACE

HCC 10

Code-level coefficient reference

RXHCC

HCC 21

Code-level coefficient reference

Code Book Path

Official
C84Mature T/NK-cell lymphomasC84.7Anaplastic large cell lymphoma, ALK-negativeC84.73Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes

Inclusion Terms

Official

No inclusion terms are included in this display for C84.73. Check the code and parent instructions in the Code Book.

Excludes 2

Official
  • Kaposi's sarcoma of lymph nodes (C46.3)Inherited from C81-C96
  • secondary and unspecified neoplasm of lymph nodes (C77.-)Inherited from C81-C96
  • secondary neoplasm of bone marrow (C79.52)Inherited from C81-C96
  • secondary neoplasm of spleen (C78.89)Inherited from C81-C96

Related Codes

Official
C84.70Anaplastic large cell lymphoma, ALK-negative, unspecified siteC84.71Anaplastic large cell lymphoma, ALK-negative, lymph nodes of head, face, and neckC84.72Anaplastic large cell lymphoma, ALK-negative, intrathoracic lymph nodesC84.74Anaplastic large cell lymphoma, ALK-negative, lymph nodes of axilla and upper limbC84.75Anaplastic large cell lymphoma, ALK-negative, lymph nodes of inguinal region and lower limb

Includes

Official

No Includes notes are included in this display for C84.73. Check the code and parent instructions in the Code Book.

Excludes 1

Official
  • personal history of non-Hodgkin lymphoma (Z85.72)Inherited from C84, C84.7
  • primary cutaneous CD30-positive T-cell proliferations (C86.6-)Inherited from C84, C84.7

Code First

Official

No Code First sequencing instructions are included in this display for C84.73. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C84.73. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C84.73. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Pathology confirming ALCL with ALK-negative status
Abdominal imaging documenting specific lymph node groups involved
CD30 positivity and T-cell markers on immunohistochemistry
Distinction from hepatosplenic T-cell lymphoma and enteropathy-associated T-cell lymphoma

MEAT Support

HCC Buddy guidance
Pathology confirming ALCL with ALK-negative status
Abdominal imaging documenting specific lymph node groups involved
CD30 positivity and T-cell markers on immunohistochemistry
Distinction from hepatosplenic T-cell lymphoma and enteropathy-associated T-cell lymphoma

Audit Caution

HCC Buddy guidance
Confusing intra-abdominal with intrapelvic lymph nodes
Coding splenic involvement as intra-abdominal lymph nodes
Using PTCL-NOS code when ALCL morphology is confirmed
Not distinguishing ALCL from enteropathy-associated T-cell lymphoma in abdominal presentations

Common Mistakes

HCC Buddy guidance
C84.63 — ALCL ALK-positive, intra-abdominal: Different ALK status
C84.43 — PTCL-NOS, intra-abdominal: Different subtype
C84.76 — ALCL ALK-negative, intrapelvic: Pelvic nodes are below pelvic brim; distinguish from abdominal
C84.77 — ALCL ALK-negative, spleen: Spleen has its own code; not an abdominal lymph node

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C84.73 an HCC code?

Yes. C84.73 (Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes) maps to HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.798. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: C84.73 is billable and maps to V28 HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
C84.73
Description
Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes
HCC (V28)
HCC 19 — Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
RAF reference coefficient
1.798
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
1.798
ESRDHCC 10, Lymphoma and Other Cancers
Not separately weighted
RxHCCHCC 21, Lymphomas and Other Hematologic Cancers
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C84.73 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C84.73

For C84.73, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

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What This Code Means

C84.73 is the ICD-10-CM diagnosis code for anaplastic large cell lymphoma, alk-negative, intra-abdominal lymph nodes. A type of aggressive lymphoma (cancer of immune cells) without a specific genetic marker (ALK-negative) that is located in the lymph nodes within the abdominal cavity. C84.73 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).

Under the CMS-HCC V28 risk adjustment model, C84.73 maps to Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers (HCC 19) with a source-labeled community, non-dual, aged reference coefficient of 1.798. No V24 mapping is shown for C84.73; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Verify specific abdominal lymph node involvement (mesenteric, retroperitoneal, etc.) through imaging or pathology reports. For C84.73, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for C84.73 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Verify specific abdominal lymph node involvement (mesenteric, retroperitoneal, etc.) through imaging or pathology reports
  • •Distinguish from splenic involvement, which has a separate code (C84.77)

Clinical Significance

Anaplastic large cell lymphoma, ALK-negative, involving intra-abdominal lymph nodes indicates aggressive T-cell lymphoma without the ALK marker affecting abdominal nodal basins. Abdominal ALCL may present with nonspecific symptoms such as pain, bloating, or weight loss. The worse prognosis of ALK-negative disease necessitates aggressive multiagent chemotherapy.

Documentation Requirements

  • ✓Pathology confirming ALCL with ALK-negative status
  • ✓Abdominal imaging documenting specific lymph node groups involved
  • ✓CD30 positivity and T-cell markers on immunohistochemistry
  • ✓Distinction from hepatosplenic T-cell lymphoma and enteropathy-associated T-cell lymphoma
  • ✓Clinical staging documentation

Commonly Confused Codes

  • •C84.63: ALCL ALK-positive, intra-abdominal: Different ALK status
  • •C84.43: PTCL-NOS, intra-abdominal: Different subtype
  • •C84.76: ALCL ALK-negative, intrapelvic: Pelvic nodes are below pelvic brim; distinguish from abdominal
  • •C84.77: ALCL ALK-negative, spleen: Spleen has its own code; not an abdominal lymph node

Child Codes

C84.70Anaplastic large cell lymphoma, ALK-negative, unspecified site
HCC 19
C84.71Anaplastic large cell lymphoma, ALK-negative, lymph nodes of head, face, and neck
HCC 19
C84.72Anaplastic large cell lymphoma, ALK-negative, intrathoracic lymph nodes
HCC 19
C84.73Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes
HCC 19
C84.74Anaplastic large cell lymphoma, ALK-negative, lymph nodes of axilla and upper limb
HCC 19
C84.75Anaplastic large cell lymphoma, ALK-negative, lymph nodes of inguinal region and lower limb
HCC 19
C84.76Anaplastic large cell lymphoma, ALK-negative, intrapelvic lymph nodes
HCC 19
C84.77Anaplastic large cell lymphoma, ALK-negative, spleen
HCC 19
C84.78Anaplastic large cell lymphoma, ALK-negative, lymph nodes of multiple sites
HCC 19
C84.79Anaplastic large cell lymphoma, ALK-negative, extranodal and solid organ sites
HCC 19
C84.7AAnaplastic large cell lymphoma, ALK-negative, breast
HCC 19
C84.7BAnaplastic large cell lymphoma, ALK-negative, in remission
HCC 19

Code Hierarchy

└C84Mature T/NK-cell lymphomas└C84.7Anaplastic large cell lymphoma, ALK-negative└C84.73Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes
└C84.73Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes

Also searched as

  • C84 73
  • C8473

For C84.73, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

C84.73 maps to CMS-HCC V28 category 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for C84.73. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

Work C84.73 in HCC Buddy

Open C84.73 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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